Slashdot is powered by your submissions, so send in your scoop

 



Forgot your password?
typodupeerror

Comment Re:Math (Score 1) 238

It's worse than that. If you RTFA, you find the 500 MW is capacity, not actual production. So it's a CSP (concentrated solar power) plant with a peak generating capacity of 500 MW.

Morocco is at about the same latitude as Southern California, and CSP there has a capacity factor of about 33%. So average power generation for the year should be about 500 MW * 33% = 167 MW. Which for 1.1 million people works out to an average consumption of 152 Watts. That's 1332 kWh/yr.

U.S. average is about 13,000 kWh/yr
UK average is about 9450 kWh/yr
Germany averages about 7200 kWh/yr
Frace averages about 7300 kWh/yr
Japan averages about 7800 kWh/yr
S. Korea averages about 10,200 kWh/yr
Morocco's average seems to be about 850 kWh/yr, which suggests their expected capacity factor is substantially lower than 33%. Using the above numbers I get a 21% capacity factor.

Comment It's the internet (Score 2) 249

There's no need for comparative statistics for men vs women, which leave you trying to control for all sorts of nebulous factors like how nicely they make requests, or how the genders might code differently.

All you have to do is take a bunch of coders (men or women, doesn't matter), and have them submit a bunch of code online using a male persona, using a female persona, and anonymously (or at least gender-neutral). Then compare acceptance rate for each individual. That neatly eliminates all other factors since you're comparing the same individual to himself or herself.

Comment Re:"Tumbling under control" (Score 1) 211

And now the Pentagon is saying it's tumbling again.

Tumbling refers to a very specific behavior in rotational dynamics. A body is only stable in rotation when it rotates around its minimum or maximum moments of inertia (inertia is a 3x3 matrix, not a single number of even a vector like they teach you in high school). When a body tries to spin around any other axis, it ends up gyrating wildly. What's happening is the spin axis is trying to align with a stable spin axis, but overshoots and passes right through it, over and over. Like a marble that tries to reach the bottom of a bowl (stable point) but keeps overshooting and rolling back and forth.

It's very difficult to recover from because the axis of spin is changing dynamically, so by the time you fire a thruster to counteract the spin, the axis may have changed and the thruster may have little to no effect, or even make things worse. I've been trying to get one of the ISS crew to shoot some video demonstrating it because it's very difficult to demonstrate on Earth. But you can sort of see it by rubber banding a textbook closed (pick one whose three lengths are very different). Spin it as you throw it into the air. Spinning it so the axis is normal to the front/back is stable. So is spinning it so the axis is normal to the top/bottom (assuming the book is taller than it is wide). But spin around the axis through the spine will result in tumbling.

Rotationally-stabilized spacecraft and satellites are carefully designed so the intended spin axis aligns with a minimum or maximum moment of inertia. Someone on the design team has a great big spreadsheet full of the inertia tensors and exact position of every single part that went into the spacecraft, so s/he can calculate its aggregate inertia tensor. If it doesn't quite line up, they have to either add/remove some weight or move some items around until it does.

Comment Re:Its not the actual bomb, its the threat (Score 1) 211

Luckily, your fears are completely unfounded. NK doesn't give a flying *** about the USA. It is more concerned with South Korea and if it was to use a nuke, they already have a target painted large as Seoul is only 30 miles from the NK border - easily reachable by truck in less than an hour. That is their hostage, should anyone attack them.

NK's entire educational indoctrination program is based on hatred of the U.S. You know how one of the best ways to unite a people is to confront them with an outside enemy? That's what NK does, using the U.S. as the outside bogeyman. You're colossally ignorant of what's going on in NK if you think they don't give a flying *** about the U.S.

40 years ago, at least most of the people in NK knew life before this political brainwashing began. But today most of the population there has grown up hearing and believing the U.S. is evil with no counterpoint argument for their entire lives. Nobody has ever done a massive social manipulation experiment of this scale for this duration, so nobody knows what the result will be, which makes NK incredibly unpredictable when it comes to anything which involves attacking the U.S.

And the ICBMs and nukes are for Japan, China, and the U.S. Holding Seoul hostage doesn't even require NK to cross the border - the city is and always has been within artillery range of North Korea.

Comment Re:Why give them 3 months? (Score 1) 167

Yeah, Facebook's tracking is why I first installed no-script (I now rely on Ghostery). You know that little "f" logo that's nearly ubiquitous on every web page to let you share the page via Facebook? That isn't just a graphic and a link. It's accompanied by a godwaful script. Every time you visit a page with that 'f' logo, your computer contact's Facebook's servers and hands over enough information (Facebook cookie, cookies for other sites, browser ID and version, system info, etc.) for them to uniquely identify your computer. If you're logged into Facebook, they add the page you've visited (with a 'f' logo) to the browsing history of your secret personal profile. If you're not logged into Facebook, they build up the profile and the moment you login, they append that browsing history to your profile.

Even if you don't have a Facebook account, they build up a profile for unknown user 512415792346. And one day when your friend emails you a Facebook invite and you happen to view it in your browser, they suddenly know that 512415792346 is in fact John Smith, because that's the name your friend has been using to tag photos of you (auto face recognition FTW) he has on his Facebook account. And your email is johnsmith@gmail.com because that's where your friend sent the invite. And that you live at 1234 Main St, Springfield, CA because that's where the GPS tagging in those photos say you're mostly at in the evenings. And you work at Yoyodyne Propulsion because you were present in photos he and other Facebook users posted of last year's company picnic. And that you're a closet furry (the sex fetish kind) because that's where the browsing history they've collected on you says you spend most of your time online. You don't even have a Facebook account and they already know everything about you.

The is the crap the French govt is trying to get them to stop doing. People who've opened a Facebook account have presumably consented to this in one of the myriad EULAs they've agreed to. But Facebook has no business tracking people who don't use Facebook and never consented to any of this.

Comment Re: I am not a physicist but... (Score 1) 329

I wouldn't be so sure. Japan was the first country to travel that route. In the 1950s Japanese products were considered garbage. By the 1980s, it was considered some of the best stuff in the world. But it's GDP per capita (nominal) has stagnated around $35k/yr vs about $55k/yr for the U.S. and $45k/yr for most of the Western Europe.

South Korea and Taiwan are the two more recent countries to advance that way (products considered to be cheap trash in the 1970s, desirable by the 1990s). But their GDP has stagnated at around $25k/yr per capita. (Yes Taiwan - nearly all laptops are designed in Taiwan). Singapore would seem to be an exception at about $55k/yr, but it's a city-state and achieves that high GDP by not having any low-income rural residents.

There is just something about these East Asian countries which is preventing them from reaching the level of productivity that the U.S. and Western Europe have reached. My theory is it's corruption (bribery is a fact of life there) and ingrained rules of society which impede free market forces from helping remove inefficiencies. If I'm right, then China, currently at about $8k/yr, is probably going to stagnate before it reaches $15k/yr due to its Communist government trying to micro-manage everything its people do. That would be enough to supplant the U.S. as world's largest economy, but it will hardly be world-leading when it comes to technologies. I mean it will have a few world-leading breakthroughs due to the sheer size of its economy and population, but the amount of technological advancements per $GDP and per citizen will be far below what we see from the U.S., Western Europe, Japan, South Korea, and Taiwan. You could even argue China has already reached its peak - $8k/yr GDP per capita is where Russia stopped at when it was the Soviet Union (inflation adjusted), and where it is right now.

Technological progress doesn't just come from dumping money into R&D. You also have to give your researchers and engineers freedom to try out all the crazy ideas they can think of. And have a free market which can sort out the good ideas from the bad (instead of some government official designating that one idea is good while another is bad).

Comment Re:Price Is Still Just One of Two Sticking Points (Score 2, Informative) 185

Oh, while we are at it, SSD tend to fail spectacularly: i.e. usually when they perish you cannot extract any information at all vs. spinning platters which usually fail gradually.

Most newer SSDs are designed to fail gracefully. When they die, they become a read-only device. All your data is still accessible. Many USB flash drives are designed to fail the same way - if you've ever had a USB flash drive mysteriously become "write-protected", it probably died and set itself to read-only mode. Unfortunately, Samsung seems to be one of the SSD manufacturers which hasn't yet adopted this philosophy for failure. But I can understand their reasoning because...

P.S. If you wanna counter my first argument, fill your SSD up to 99% and then try to work with it continuously for quite some time. That 1% will get overwritten multiple times and your whole SSD will be prone to a failure.

That problem was solved in the 2000s with wear-leveling algorithms. Basically, the "sectors" the SSD presents to the computer aren't actual physical locations. They're virtual locations stored in a table. If the SSD senses certain blocks being used too much or other blocks sitting unused, it moves the data around behind the scenes so that writes hit all flash memory cells about equally. It updates the virtual table every time it does this, to fool the computer into thinking the drive is physically the same as it has always been.

The rated endurance on most consumer SSDs is around 2000-3000 cycles. For a 250 GB SSD, that means you can write 625 terabytes to it before expecting a failure. If you write 100 GB of data to the drive every day, you can expect it to last nearly 20 years. In torture tests, most SSDs have lasted about 2-3x longer than their rating. And no, the first cell failure is not catastrophic. Pretty much all SSDs have a number of reserve cells sitting on the sidelines to take over for cells which fail early.

If your duty cycle is higher than 100 GB/day, they make special enterprise SSDs rated for 10k-100k writes per cell. The price is correspondingly higher of course, primarily due to using SLC (one bit stored per cell) instead of MLC (2 bits) or TLC (3 bits).

Limited number of writes were more of a problem in the early days of SSDs when they were like 32 GB in size. In that case, the exact same characteristics as the above 250 GB SSD would yield only 2.2 years of longevity. But the problem has pretty much become a non-factor as capacities have increased.

Comment Re:so what? (Score 1) 286

What about the US' ability to attack everyone? How about those pricks disarm and reduce their military to 1/10th the size, stop toppling governments because they don't like them etc?

You're mixing up capability with likelihood. Total risk is the product of the two. The U.S. has had nuclear-capable ICBMs for over 50 years now, but has never used them. So while it has had the capability for a long time, the proven likelihood that it'll use them is very low, even when it's been provoked. The reason people (not just the U.S.) is concerned about North Korea's capability is because its leadership is extremely erratic and unpredictable, so the likelihood it would actually use ICBMs is a lot higher than existing nuclear powers'.

Also, U.S. military spending is huge only if you look at it in raw dollars. That's like looking at the raw dollars a large wealthy household spends on food, and comparing it to what a homeless individual spends. If you insist on looking at it in raw dollars, we could divide U.S. military spending across all 50 states (many of them are larger than most countries) and *poof* - the individual states no longer have the world's largest military spending.

The proper normalized metric is spending (any type, not just military) as a percent of GDP. That eliminates the effect of wealth and population. Basically, what percentage of your citizens' productivity do you direct to your military? By that measure, U.S. military spending is about 3.5% of its GDP. That's only about 1.5x the world average of ~2.3% of GDP. By that measure, the U.S. doesn't even make the top 25 in military spending. And that's not even factoring in Japan, which the U.S. is contractually obligated to defend by the terms of peace treaties signed ending WWII. Include Japan's GDP and U.S. military spending drops to about 2.7% of aggregate GDP. If you cut U.S. military spending to 1/10th what it is now, it would have just about the lowest military spending of any nation on earth.

Incidentally, guess which country spends the most on its military as a percentage of GDP.

Comment Boat still hasn't left port (Score 4, Interesting) 267

Bitcoin made a lot of progress on the technological front, but its economics is flawed because it limits the number of bitcoins which can be mined, and makes them progressively harder to mine as more are found. This is the same flaw behind using gold as your currency standard, and will cause the same problem - economic instability via repeated bouts of deflation. Basically, because the amount of gold (bitcoins) doesn't grow as quickly as the size of the economy, prices for things in that currency start to go down.

Vastly simplifying the economy into one currency and one product, today there are x bitcoins and you make y widgets. The price for a widget is thus proportional to x/y. Tomorrow, the number of bitcoins hasn't increased as quickly as your economic activity is increasing. There are 1.2x bitcoins, but you make 1.5 widgets. The price for a widget becomes proportional to 1.2x/1.5y = 0.8x/y. In other words, deflation - a widget is only worth 80% what it was yesterday.

Now apply the same principle to all goods and services, and the price of everything is going down (actually the price of bitcoins is going up). Once people start to understand what's happening, they stop buying things. They want to wait until the last possible minute, until they absolutely need an item, to buy it because the longer they wait (the longer they hold onto their bitcoins), the less it will cost. This slowdown in economic activity causes a recession, which decreases the number of widgets that are made until once again their price goes up (because not enough are being made to meet demand), which starts the same process over again. Economic instability.

That's why every major economy has abandoned the gold standard for a fiat currency. Yes a fiat currency can be abused if the people in charge of it are corrupt. But used properly with the money meted out at about the rate the economy is growing, prices remain stable and so is the economy. Just look at the list of recessions in the U.S. pre-1933 and post-1933 when the U.S. went off the gold standard. The economy has been much more stable with a fiat currency. That's what needs to happen with a cryptocurrency for the "boat to leave port." If someone can come up with a cryptocurrency which is independent of central control, yet its supply increases at roughly the same rate the economy expands, that is the boat you want to get on. It just won't be as lucrative for early adopters as bitcoin because it won't be a ponzi scheme.

Comment It's an e-reader, not paper (Score 1) 151

The whole point of a LCD or e-ink display made of pixels is that you can display whatever you want. There's no requirement like paper where you have to pick a font and your'e stuck with it. Manufacturers need to let the device's owner load up and use whatever fonts they want. I mean sure the publisher and device manufacturer can recommend a font, but they have no business dictating what font is used on your device. Forcing you to use one particular font is like making a radio with a tuning knob, but only allowing you to listen to one station.

Comment Re:You Live In The Wrong Time Zone. (Score 1) 110

Changing time zones is only a temporary fix. My body's internal clock seems to be set for a 25 hour day. The early riser's internal clock seems to be set for a 23 hour day. I'm slow to get up but can work well into the night. They get up early, but crash sometimes before it's even dark outside.

Comment Re:Grace? (Score 1) 582

To get a ticket for going 34 mph in a 25 mph zone usually means you angered a cop,

Doesn't really work like that. You're assuming there are two variables - how fast you were going, and the speed limit.

There are actually three variables. How fast you're going, the speed limit, and how fast the cop says you were going. I was going about 45 mph in a 40 mph zone (used to be a 55 mph zone when I lived there a decade ago so I thought I was far under the limit). On the ticket, the cop wrote that I was going 55 mph just to get around that pesky 10 mph grace. Best I can tell, he was upset that I did a jackrabbit start from a red light, which I did to pass a slow car I'd been stuck behind (the road split into two lanes for a short span at the light). I'm a pretty safe driver and very aware of what I'm doing - that's my only ticket in over 30 years driving.

Slashdot Top Deals

Mirrors should reflect a little before throwing back images. -- Jean Cocteau

Working...