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Comment: Re:Memorizing site-unique passwords isn't possible (Score 2) 190

by Rei (#49350175) Attached to: Generate Memorizable Passphrases That Even the NSA Can't Guess

Yeah, the suggested method for generating passwords generates needlessly long passwords. The total entropy is good, but the entropy per character is pretty poor. You get much better entropy per character with abbreviation passwords, where you have a sentence or group of random words and you use the first letter from each, or second, or last, or alternating, or whatever suits you. It's still not as much entropy per character as a random pattern, but it's much better than writing out full words - and pops into your head just as fast (because it is, in essence, the same).

Comment: Re:what will be more interesting (Score 5, Insightful) 519

by Rei (#49345311) Attached to: Jeremy Clarkson Dismissed From Top Gear

Are people really going to miss yet another totally fake show pretending to be reality? Is it just because this one combined cars and Daily Mail-style politics?

Sorry, but I have no sympathy for a primadonna for whom curses at an employee for 20 minutes and then physically assaults him up for half a minute (without any resistance from his victim) before someone pulled him off, all because the Clarkson's food wasn't warm. And this is hardly the first time Clarkson has behaved like this, he was already on "final warning" after a string of other incidents. What befalls him is his own bloody fault. And all of the abuse that the victim got over this whole thing... my favorite tweet on the subject was:

"Man assaults another man and victim receives abuse because people can’t watch a TV show about cars. Bravo society. "

Comment: Most of Japan is very beautiful... (Score 4, Interesting) 183

by Rei (#49342927) Attached to: Japan To Build 250-Mile-Long, Four Storey-High Wall To Stop Tsunamis

.... but their beaches, usually not so much. So hopefully this won't be too much of an eyesore. Japan is usually pretty good about trying to fit human-made structures into the landscape; my friends and I had a running joke when we were there: "They have the prettiest drainage ditches here!" ;) That said, a 250-mile long, 4-story "anything", that's going to be hard to make look nice.

I'm rather curious about what kind of concrete they're going to use. Japan has been a pioneer in the use of fiber-reinforced concrete, I wonder if they'll use that in lieu of steel that may need cathodic protection in such a high salt environment?

Comment: Re:Keyword "apparently" (Score 1) 102

by Rei (#49342817) Attached to: The One Thousand Genes You Could Live Without

Well, not exactly. The answer to the question of how the immune system can defeat a foe that is mutating and evolving so quickly is "it also is mutating and evolving quickly". Immunoglobulin genes in B cells mutate very rapidly. Those whose antigen binds best with an invader are stimulated to reproduce (and evolve more), ultimately differentiating into plasma B cells (whose job it is to mass produce antibodies) and memory B cells (which stay alive for long periods of time, allowing the body to "remember" how to fight off an invader that it fought off in the past).

That said, this only applies to genes responsible for antibody production, and only in B cells.

Comment: Re:floppy disk (Score 2) 102

by Rei (#49342779) Attached to: The One Thousand Genes You Could Live Without

Where do you get that? Wikipedia says that the human genome is 3,23473 billion base pairs. I mean, you could compress that to fit on a CD, but it won't fit at one byte per BP. Won't even fit at 2 bits per BP.

And if we want to think of a BP like a letter in a piece of code, with an average programming code line length of say 15 non-whitespace characters, that corresponds to a program 216 million lines long. That'd be no little program...

Of course, only a tiny fraction of our DNA codes for what we would consider to be the "interesting stuff".

Comment: Re:Given that humans still struggle... (Score 1) 126

by Rei (#49340169) Attached to: Do Robots Need Behavioral 'Laws' For Interacting With Other Robots?

Part of the premise to the problem is that you know it will work. If you'd rather, you can look at the scenario of a doctor with several dying patients who need transplants deciding to kill one of his other patients to save the lives of all of the others. It's a question of where the boundaries to sacrificing one to save multiple becomes troubling to people. Knowing how to define these boundaries are critical to being able to program acceptable "morality" in robots.

Comment: Given that humans still struggle... (Score 5, Insightful) 126

by Rei (#49336659) Attached to: Do Robots Need Behavioral 'Laws' For Interacting With Other Robots?

... to even understand why we consider certain judgements to be moral or immoral, I'm not sure how we're supposed to convey that to robots.

The classic example would be the Trolley Problem: there's an out of control trolley racing toward four strangers on a track. You're too far away to warn them, but you're close to a diversion switch - you'd save the four people, but the one stranger standing on the diversion track would die instead. Would you do it, sacrifice the one to save the four?

Most people say "yes", that that's the moral decision.

Okay, so you're not next to the switch, you're on a bridge over the track. You still have no way to warn the people on the track. But there's a very fat man standing on the bridge next to you, and if you pushed him off to his death on the track below, it'd stop the trolley. Do you do it?

Most people say "no", and even most of those who say yes seem to struggle with it.

Understanding just what the difference between these two scenarios is that flips the perceived morality has long been debated, with all sorts of variants for the problem proposed to try to elucidate it, for example, a circular track where the fat man is going to get hit either way but doesn't know it, situations where you know negative things about the fat man, and so forth. And it's no small issue that any "intelligent robots" in our midst get morality right! Most of us would want the robot to throw the switch, but not start pushing people off bridges for the greater good. You don't want a robot doctor deciding to kill and cut up a patient who in the course of a checkup discovers that the patient has organs that could save the lives of several of his other patients, sacrificing one to save several, for example.

At least, most people wouldn't want that!

Comment: Re:Wouldnt NiFe be a better battery chemistry here (Score 1) 184

by Rei (#49336047) Attached to: Elon Musk's SolarCity Offering To Build Cities, Businesses Their Own Grids

Again, it's simply not. You keep acting like cost per kW is irrelevant. This is absolutely not the case. You're the one trying to hand wave away the power input and output demands of stabilizing a renewables grid. According to your logic, people would never use li-ion for grid storage. Except that they actually do. In new projects it's more common than PbA for the large (greater-than-datacenter) scale (PbA still dominates at the datacenter scale, and probably will for some time to come)

I would say that you have obviously never worked with lithium batteries. Tesla does not use large format cells. It uses 18650-format cells. One never messes with individual cells, the bricks are designed to allow multiple concurrent failures without significant degradation in performance. And saying that something is "yet to be seen" does in no way shape or form mean "using defunct packs is bull", and it's beyond me how you could read that into that statement. Furthermore, it's also funny how you read that section but entirely missed the lines before it:

Considerable interest has been generated in the last 2 to 3 years for applying lithium-ion batteries for a variety of energy storage and grid stabilization (stationary) applications. Prototype systems have been installed. Megawatt scale systems typically include thousands of cells housed in shipping container-sized structures that can be situated on power utility locations. These systems usually include integrated fire suppression in their installations. Smaller systems have also been planned and are being delivered for evaluation purposes, particularly for use with renewable energy sources.

Gee, I thought nobody would want to use li-ion for grid backup? ;)

Comment: Re:Wouldnt NiFe be a better battery chemistry here (Score 1) 184

by Rei (#49334119) Attached to: Elon Musk's SolarCity Offering To Build Cities, Businesses Their Own Grids

Tesla packs highly resistant to "failing internally". Each brick is made of dozens of cells wired in parallel. It's irrelevant if a handful of cells totally die.

The li-ion charge retention curve is usually an exponential decay. The lower the capacity of the cell gets, the slower further degradation goes. Now, in many electronic devices, it doesn't seem this way because the device is designed for a particular operational voltage range, and when the pack gets below that voltage it's totally useless. But a large-scale system engineered to use old packs and thus designed for greater voltage flexibility is not bound by this constraint.

Comment: Re:Wouldnt NiFe be a better battery chemistry here (Score 1) 184

by Rei (#49334113) Attached to: Elon Musk's SolarCity Offering To Build Cities, Businesses Their Own Grids

False. Cost per kWh can be everything or it can be utterly irrelevant, depending on the needs of the backup system. The facts that matter are the particular mix of cost per kWh AND cost per kW needed by the system. Many if not most li-ion batteries have a higher ratio of W to Wh than PbA. Hence saying that "li-ion batteries are expensive" and using a price per Wh as the basis is erroneous.

Furthermore, costs for large backups are not as simple as multiplying the cost of building things out of X number of small cells. Economies of scale come into play, shipping and housing issues come into play, heating and efficiency come more into play, environmental permitting factors come more into play, hazards come more into play, and all sorts of other factors. Many people worry about fire risks from li-ion, for example (although that's not the case with all li-ion types). But in large quantities, PbA batteries become an explosion hazard, as in some circumstances they can outgas hydrogen. Large PbA battery backups have ended in explosion before.

The meat is rotten, but the booze is holding out. Computer translation of "The spirit is willing, but the flesh is weak."

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