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The advantage of GrabCut compared to the parent article is that it takes both color difference and similarity into account rather than just difference. This is done by combining all that information into a very cleverly-laid-out Markov Random Field where making an energy-minimizing graph cut roughly corresponds to finding a better pixel classification.

The disadvantage compared to the parent is that it's a semi-supervised algorithm: it requires a bounding box to be drawn around the desired image. If you had a bunch of very similar images you could pre-generate the Gaussian Mixture Model that GrabCut expects and turn it into a supervised learning algorithm, but then you'd lose the major innovation of GrabCut compared to the graph cut methods discovered before it: you would not be able to re-run with the newest "best-guess" and be guaranteed that the energy would monotonically decrease. It would also fail spectacularly if it encountered something it hadn't seen before.

When you say your 1 BTC is on your hard drive, do you mean it's on the hard drive of a running Internet-connected computer? If so, how do you address the threat of malware that searches for wallet files?

Can you expand on your opinion regarding NASA's problems stemming from "failure is not an option?" Based on Gene Kranz's Wikipedia page, specifically the "Failure is not an option" section ( http://en.wikipedia.org/wiki/Gene_Kranz#.22Failure_is_not_an... ), this is a complicated and controversial topic.

Joel Spolsky wrote a good article about this called "Back to Basics" (src: http://www.joelonsoftware.com/articles/fog0000000319.html ). My favorite quote from it (capitalization modified) is, "If you want to teach somebody something well, you have to start at the very lowest level. It's like Karate Kid. Wax on, wax off. Wax on, wax off. Do that for three weeks. Then knocking the other kid's head off is easy."

This is the best general explanation I've seen: http://www.techrepublic.com/blog/software-engineer/templeos-...

A Linux operating system has a core program called a kernel, which has the job of creating and maintaining an environment where other programs can run. Other programs include the login prompt, the shell that lets you execute programs, etc. However, there is a chicken-and-the-egg problem: once the environment is running, how do you run the first program? This is solved by having the Linux kernel run a program called "init" as the first program, which manages everything else (bringing up services, executing the login prompt, etc). There are multiple versions of this "init" program with different features and idiosyncrasies -- the Debian committee voted to use one called systemd rather than some competitors. Switching versions of init requires system administrators to relearn how to do many things, so the committee spent a lot of time weighing a lot of factors before making this decision.

Why did the military require human beings to turn the keys if they expected people (and weeded out people unwilling) to turn the key blindly? A wire would have been much more efficient...

How do you define virtual? Is it limited only to simulations, or is it for any attempt to mimic nature? For example, organic compounds used to be considered impossible to synthesize due to a "vital force" until Wohler synthesized urea from inorganic compounds. Is organic chemistry the study of "fake" organic compounds?

There are two major competitors to the Von Neumann architecture, and then a few speculative ones. The most popular one is Harvard architecture, where code and data are in separate memories (improves security and performance, but makes loading code difficult). Most modern processors operate like a Harvard architecture machine when they are running directly from cache, but they act like Von Neumann machines when they have access to RAM. This means that they get some of the performance benefits, but you need hacky things like W^X to get (partially) the security benefits.

The other one is dataflow architecture, which involves representing programs as a digraph where nodes represent instructions. Data flows through edges from one instruction to the next non-deterministically. This was popular research material in the late 70s and early 80s, but there were efficiency concerns.

IBM (and Von Neumann) also dabbled with making computers that resembled neural networks, but VN passed away before he could dedicate a lot of time to it. AFAIK IBM's neural computer is still in research phase.

I'd say Von Neumann machines "won" for a few reasons. First, Von Neumann consulted for IBM in the department that developed their first commercially-sold computers, so he got a lot of creative control. Second, as Hennessey and Patterson wrote in Computer Architecture: A Quantitative Approach, advocates of Von Neumann computers regarded HA machines as reactionary, implying there was even some religion back then. Third, Von Neumann architecture machines are significantly easier to load programs into. My guess is that a combination of business/political concerns on IBM's part in the 50s and 60s combined with momentum and switching costs is the main reason VN machines continue to win.

What I believe low-level computing teaches you is that fundamental computation hasn't changed (architectural or system-level) for decades. We've had Lisp (and its associated software improvements) since the late 50s, protected memory and multitasking since the late 60s (OS/360), virtualization and security since the early 70s (VM/CMS, Bell–LaPadula Model), GUIs/networking since at least the mid-70s (Xerox PARC), and formal computer security models since the mid-80s (Rainbow series). In the last few decades we've seen some dramatic improvements in semiconductor miniaturization, a couple architectural improvements (just off the top of my head, ASLR, W^X, and the Pentium's RISC-to-CISC design, though there are some others), and then mostly a lot of integration (computer+phone, computer+car, computer+plane, etc) and software craftsmanship based on principles developed decades ago. I'm not knocking craftsmanship (we all pay the bills practicing it), but due to design decisions made decades ago (such as the security nightmare that is Von Neumann architecture) we base software quality on how few mistakes individual artisans make rather than design systems that prevent artisans from making mistakes.

A great way to become a cynic and pessimist about programming is to get a computer engineering degree. Once you understand computers at the gate & flip-flop level, you realize that most of what people argue about on the Internet is window dressing.

One in six women in the US have experienced an attempted or completed rape in their lifetime (src: https://www.ncjrs.gov/pdffiles/172837.pdf ). Is it worth potentially inducing PTSD symptoms to use that subject matter in this question? I'd say no.

The question (src: http://i.imgur.com/CwegI9i.png ) is a Prolog problem, which is just a bunch of logical premises that the system is supposed to find the conclusion for (kinda like A=>B, B=>C, therefore A=>C). The problem doesn't involve analyzing communications or predicting anything, and it would have little or no use when developing social network systems.

I think they should say that Google's lab rewards doing research, not rewarding failure. Managerial incentive systems' biases toward positive results holds the entire R&D community back.

I like the word "workshop" instead of "school" as mentioned in their FAQ under "Experience" (src: https://www.hackerschool.com/faq ). However, that implies something like a makerspace, which doesn't seem to be the type of thing they're going for.

I'm feeling pretty judged by this comment.

In my high school, I remember being introduced to functions of that type in Algebra II and at the very latest trigonometry (sines and cosines).

While a knowledge of functions is vital to understanding Calculus (the fundamental theorem of calculus depends on them), it's only a small component of the bigger picture. Calculus is mainly about how functions change with respect to some other variable (time is common) and the inverse of that operation.

It would take too much secret coordination, but the coolest thing would be if all the world's encryption experts/academics colluded to talk at RSA's conference with seemingly-plausible topics, but then have everyone just deliver a speech on RSA's actions before leaving the podium. Then again, getting in would require writing legitimate papers that RSA could still publish in their proceedings to make the conference look successful.

The author says that scientific and technological progress in certain fields is outpacing human morality, but he or she advocates advancing science and technology toward better understanding human morality. Presumably, this would entail understanding and modifying the chemistry of our bodies to eliminate the "baser animalistic drives" caused by evolution. However, if our species is so immature, how do we know that our modifications are moral? How do we make sure the people wielding this awesome power aren't immoral themselves?

The cynical side of me says that the ISP is just going to redirect the author's traffic to the "pure" DNS server in the future (even when he or she directs traffic to the main one) unless they get in serious enough trouble with one of the companies this first time.

If anyone wants to do this in the future, I'd recommend just sending affiliate abuse emails with no notice to the ISP. Also, the future person may want to revise the [2] script to scan in a more surreptitious manner (change the order, add delays, simulate legit web traffic, etc).

The difference between the office example and the gun example is that the generalized version would actually make sense in the office example (for example, here is Derek Sivers bringing a similar argument up: https://sivers.org/punish ). If you were my coworker saying the generalized version to me in an office, I would have interpreted you as having the generalized opinion. Of course, since I agree, I wouldn't have raised a counterexample, and you would have walked away thinking I agreed with what you meant instead of what you said. Language is tricky like that.

"When I use a word," Humpty Dumpty said, in rather a scornful tone, "it means just what I choose it to mean—neither more nor less."

You used a rhetorical flourish that made your argument sound more extreme than you intended, and it backfired when someone called you out on it. Rather than write a reply dripping with sarcasm and contempt, perhaps you should meditate on this incident as your personal failure to be a clear and effective writer.

This is Hacker News -- you are expected not to be sloppy with your argumentation here. If you say "inanimate object" rather than gun, then we're going to assume you are making a more general statement and react accordingly. I cannot read your mind, so please do not assume I (or anyone else) knows your precise opinion on gun control without being precise with your words.

I don't think these two incidents are comparable.

Jamie's diary page (src: http://www.jwz.org/gruntle/nscpdorm.html ) says at the top that the excerpts might serve as a cautionary tale about working in a startup (and Arrington also says in his infamous article (src: http://uncrunched.com/2011/11/27/startups-are-hard-so-work-m... ) that people who think they are working too hard or sacrificing too much should quit their startup), but aside from that it's a just a bunch of entries from a personal diary, not a rant with an overarching message or thesis statement. Arrington used the diary entries as evidence that the startup experience was hard in 1994, but (correct me if I'm wrong) he never modified jwz's quotes or tried to make it appear that jwz had an opinion that he didn't have.

> As I stated elsewhere, the government using its powers to restrict ownership of an inanimate object based on what another individual may or may not do with their own inanimate object is a disgusting abuse of power.

Do you believe the government should restrict personal ownership of nuclear weapons, or is that a disgusting abuse of power?

I think the argument only applies depending on your definition of "risk for suicide" and whether you believe there are people who never under any circumstances in their lives feel suicidal even for a second before snapping out of it.

Killing yourself requires two things: the will to do it and a means. If you have a loaded gun, the means is a constant: at any point in time you have it you could use it to kill yourself. Will, on the other hand, is a function dependent on a bunch of things: bad news, time, emotional state, social interactions, etc.

I would define "risk for suicide" in terms of the combination of both will and means. As such, unless the individual's will to commit suicide is absolutely and always zero, adding a reliable means would always increase risk of suicide. I guess it's up for debate whether there's anyone on the planet who has never felt suicidal for even a second in their lives.

I think this depends on whether you're looking at funding from a business-centric or founder-centric perspective. The business-centric contention is that you should only seek funding once you have a business idea that all your analyses show would be immensely profitable except for your company's lack of money, since otherwise you're adding unnecessary risk.

Founder-centric organizations like Y Combinator (I've never been funded by Y Combinator so please correct me if I'm wrong with this assessment) seem to have different dynamics and motivations. Instead of investing in the business, they invest in the people much like a college -- realize they are going to screw up from their inexperience, but give them angel-level amounts of money, latitude to pivot, and world-class networking opportunities and help.

In similar articles referencing mise-en-place from a business/programming/hacker context (such as http://thirdhandworks.com/2013/02/noted-mise-en-place/ ), there is a great quote from Anthony Bourdain's Kitchen Confidential:

“I worked with a chef who used to step behind the line to a dirty cook’s station in the middle of the rush to explain why the offending cook was falling behind. He’d press his palm down on the cutting board, which was littered with peppercorns, spattered sauce, bits of parsley, bread crumbs and the usual flotsam and jetsam that accumulates quickly on a station if not constantly wiped away with a moist side towel. ‘You see this?’ he’d inquire, raising his palm so that the cook could see the bits of dirt and scraps sticking to his chef’s palm, ‘That’s what the inside of your head looks like now. Work clean!‘”

Probably the nicest page I've seen on the subject is DIY Drones ( http://diydrones.com ), which covers both fixed-wing and copter-based UAV engineering. Their fixed-wing autopilot is called ArduPlane ( http://plane.ardupilot.com ).

This is a hard question to answer without knowing what types of problems your hacker friends like to solve. For example, quadcopters tend to cater to certain types of problems (mapping, precise control, etc), while fixed-wing aircraft tend to cater to a different group (autopilots, longer-distance flights, etc).