Google Challenge Results In Astoundingly Efficient Inverters 245
AmiMoJo writes: A few summers ago, Google and IEEE announced a one million dollar prize to build the most efficient and compact DC to AC inverter. It was called the Little Box Challenge, with the goal of a 2kW inverter with a power density greater than 50 Watts per cubic inch. Typical solar inverters have a density of about 5 W/cubic inch. Now the results are in, with the winners hitting 143 W/cubic inch using GaN transistors, and two other teams meeting Google's goal.
Hooray for science (Score:2)
The world is a slightly better place.
Efficiency (Score:5, Insightful)
This doesn't seem to be about efficiency at all, but rather about power density (how much power can be converted in a particular cubic volume.)
Not that small isn't a worthy goal, but efficiency is important in any application where available power isn't both free and copiously oversupplied.
Re:Efficiency (Score:4, Insightful)
Don't they go hand-in-hand though? You can only dissipate so much (waste) energy in a particular cubic volume. Decreasing the amount of waste energy increases the amount you can pack together. It wouldn't be a challenge if you're just looking for miniaturization.
Re:Efficiency (Score:4, Interesting)
Maybe, though Hack-a-Day say it involves an "incredible thermal management solution," which doesn't sound like they've actually bumped the energy efficiency up that much.
Why were Google so keen to have an inverter that maximises power density? Why not maximise energy efficiency?
Ideally you'd like to minimise cost of energy. But I guess it's fairly difficult to construct a competition around this: It depends too much on production scale and the prevailing cost of electricity. But why power density as a substitute?
Re:Efficiency (Score:5, Interesting)
Batteries. Current inverters are rather large compared the batteries that can provide their maximum output power.
Electric vehicle charging would benefit from this. You want to be pushing 120kW+ DC into the battery. You can also go back the other way and run your house from the car battery to save money when your solar panels are not producing anything.
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The inverters used for 120 kW+ charging isn't in the car, it's in the charging stations. The only charging stations hitting 120 kW+ are Tesla's superchargers, which are pure DC as far as the car is concerned.
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Re:Efficiency (Score:5, Insightful)
Electrical Efficiency is loosely coupled to volumetric efficiency. We're talking about an inverter roughly the size of a fist that's outputting 2kW. Without very high efficiency your cooling solution would be larger than your inverter. A moderate size CPU cooler (sinking ~65w) is the size of this whole inverter.
The rules require efficiency >95% which is typical for high efficiency inverter systems. At that, the primary benefit to higher efficiency is lowered cooling requirements (i.e. size) which is the primary goal of the competition.
So the rules basically *do* set teams out to maximize efficiency. Having small, highly efficient inverters is useful is many applications (solar, vehicular, UPS, etc.)
As for Google's exact benefit? I could see them running these in datacenters: deliver 450VDC rails to all your racks and power them off a hockey puck inverter or two. Simple to scale - add more battery, more racks with inverters as needed. Everything becomes modular.
Beyond that, solar and larger UPS systems typically run at 450VDC - so this means you can also scale your UPS and solar installation in conjunction with your datacenter. Basically combine all the technologies together without requiring large monolithic components. Ok, TLDR my own post.
Re:Efficiency (Score:5, Insightful)
They can go hand in hand; they don't have to go hand in hand. Generally speaking, efficiency of power conversion is fairly high, 95% isn't all that uncommon for a design that tries hard. Some of the problems are that when you're doing conversion at the KW level, 5% is 50 watts, which tends to be RFI (both direct and indirect) and heat - that's efficient in one sense, and a serious problem in another. Going from 95% to 97.5% cuts that to 25 watts; and that's not space saved once per installation, that's money saved and more energy for other things and less crap in the air every moment the conversion is ongoing.
In the case of houses and cars, where KW is the order of the day, space is a minor problem; efficiency is the major problem. I'd take a 97.5% efficient box at 10x the volume over at 95% converter any time. But it isn't even 10x the volume, generally speaking.
That's why the first thing I looked for was competition for conversion efficiency, and why I was a little put off by it not even being there.
Re:Efficiency (Score:4, Informative)
According to [1], the winner achieves 95.4% efficiency - not actually that impressive as inverter efficiencies go.
[1] http://littleboxchallengecetpo... [littleboxc...tpower.com]
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According to [1], the winner achieves 95.4% efficiency - not actually that impressive as inverter efficiencies go.
So, in the space saved, they can fit a small stirling engine? :)
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They are dissipating 92 (2kW @ 95.4%) watts in a 13.77 cubic inch enclosure and it's only heating 19 degrees above ambient.
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There is always liquid cooling. A data center usually has a decent water chilling system present, so if inverters could be cooled by that (likely via a heat exchanger, so a leak wouldn't be a major disaster), it would be more efficient than ones that are air cooled. Liquid cooling is maturing slowly, but surely, the main advance are better closed loop systems which make it easier to go this route.
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The winner runs at 48 degrees in a 29 degree environment.
A laptop PSU runs hotter than that at full load, and it's only transferring 60W, not 2000.
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Yeah... from the website [littleboxchallenge.com]:
INTRODUCING THE LITTLE BOX CHALLENGE
An open competition to build a (much) smaller power inverter, with a $1,000,000 prize.
Design and build a kW-scale inverter with the highest power density (at least 50 Watts per cubic inch).
Efficiency is not mentioned anywhere. I see somebody arguing that efficient with space is still being efficient. This is true, but is not what is commonly meant when referring to the efficient of an inverter, and misusing the word in this context is confusing.
Re:Efficiency (Score:5, Informative)
If you had read the challenge when it was proposed (or went to read the rules), the efficiency was required to be > 95%
. Produce a DCAC conversion efficiency of > 95%
From https://www.littleboxchallenge... [littleboxchallenge.com]
Re:Efficiency (Score:5, Insightful)
Ah, I didn't look that closely to see that. On the other hand, I still wouldn't consider them 'astoundingly efficient' as the headline claims. This article [electronicdesign.com] discusses a design for a 97.09% efficient inverter. (I admit at this point I'm beginning to be argumentative, but I still think the headline should have been astoundingly dense inverters, though my theory is that slashdot injects in intentional errors to drive comments and traffics from those who like to nitpick submissions).
Astoundlingly dense (Score:4, Funny)
There's probably a joke to be made at your expense, here.
Re:Efficiency (Score:5, Informative)
Ah, I didn't look that closely to see that. On the other hand, I still wouldn't consider them 'astoundingly efficient' as the headline claims. This article [electronicdesign.com] discusses a design for a 97.09% efficient inverter. (I admit at this point I'm beginning to be argumentative, but I still think the headline should have been astoundingly dense inverters, though my theory is that slashdot injects in intentional errors to drive comments and traffics from those who like to nitpick submissions).
I disagree that you're being argumentive. While efficiency can mean a lot of things, it's a dead lock given that in a story about electric inverters, that efficiency would mean conversion efficiency.
Because the "efficiency" they were actually referring to was efficiency in th enature of efficiency apartments.
I certainly don't want to disparage what they did, because it was very impressive. This was more an issue with the person who wrote the original article.
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Given that the challenge was specifically to come up with *space* efficient inverter designs, it's dead certain that the 'astoundingly efficient' comment refers to *that*, not conversion efficiency. (Given that the designs are required to be 95%+ efficient on the conversion metric, and that isn't atypical for less space-efficient designs, that's a further indicator that 'astoundingly efficient' refers to space requirements.)
Go ask an EE what they think of when dealing with efficiency in inverter circuitry. Given that I'm not the only one noticing the headline was misleading, I'm not alone at all in my response.
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> If I press really hard during those, it almost stings a tiny bit.
Err... I can save you the expense of a doctor's visit! It's stinging because, you know, you're pressing really hard. Just a guess. Don't do that and the problem will go away.
"Doctor, it hurts when I hit myself with a hammer."
"Don't hit yourself with a hammer."
That'll be $50 and schedule a follow-up in six months with the secretary out front.
Disclaimer: I am, technically, a doctor. I am not a medical doctor. Consult a qualified medical pr
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Re:Efficiency (Score:5, Informative)
From the website https://www.littleboxchallenge.com/:
In brief, the other specifications are :
* Must be able to handle up to 2 kVA loads
* Must achieve a power density of equal to or greater than 50 W/in3
* Must be able to handle loads with power factors from 0.7–1, leading and lagging in an islanded mode
* Must be in a rectangular metal enclosure of no more than 40 in3
* Will be taking in 450 V DC power in series with a 10 O resistor
* Must output 240 V, 60 Hz AC single phase power
* Must have a total harmonic distortion + noise on both voltage and current of 5%
* Must have an input ripple current of 20%
* Must have an input ripple voltage of 3%
* Must have a DC-AC efficiency of greater than 95%
* Must maintain a temperature of no more than 60C during operation everywhere on the outside of the device that can be touched.
* Must conform to Electromagnetic Compliance standards as set out in FCC Part 15 B
* Can not use any external source of cooling (e.g. water) other than air
* Does not require galvanic isolation
Google suckered everyone (Score:4, Insightful)
Sounds like Google had very specific design requirements and didn't want to spend the money in house doing development. So they dream up a contest and offer a cash prize. Meanwhile Google saves way more than the $1 million they paid out.
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Sounds like Google had very specific design requirements and didn't want to spend the money in house doing development. So they dream up a contest and offer a cash prize. Meanwhile Google saves way more than the $1 million they paid out.
Are you implying that Google somehow assumed ownership of the designs? TFA didn't say that the submitted designs ended up belonging to anyone aside from the submitters; it was, in fact, mute on the subject of ownership. Do you have a source to cite that says Google ended up owning any of the designs?
Re:Efficiency (Score:4, Funny)
They want to put it in your mobile phone! Have a solar panel on the one side, your house fuse box on the other, and your phone in the middle! That's why they wanted the highest energy density per volume!
Re:Efficiency (Score:5, Informative)
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I don't understand your attempt at pedantry. Density is spacial efficiency. If you make something smaller, you make it more efficient in the dimension of size.
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Space efficiency is technically a type of efficiency as well as all the other points above. :)
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Space efficient :-p
Also, smaller may additionally imply cheaper, or lighter.
Watts per cubic inch? (Score:3, Insightful)
Are guys fucking serious?!?
If you really want to use your old units, why not horse power per cubic inch?
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Electricity post-dates the metric system, so the US uses SI units for electricity.
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If you really want to use your old units, why not horse power per cubic inch?
Or BTU per hour per inch squared. The great thing about imperial is that there's no shortage of choice.
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Wouldn't that be 3.05MW/m^3?
Does any one know : HVDC inverters (Score:2)
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The first iteration was around 80% conversion efficiency, but I understand they are in the low 90% range now. The challenge is the IGBTs need to be chained for the voltage, which increases switching losses.
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Doh. Looks like the new yards are about 500' square by (say) 30' operating height, at 3.2GW that gives you about 4W/cubic inch. But the satellite images are kind of old and poor quality so it is hard to tell for sure where the separation between the AC substation and DC equipment really is.
GaN Transistors are the future (Score:5, Informative)
Gallium Nitride transistors have a lot of nice characteristics, but low yields and high costs have slowed their introduction. Two tiny laptop chargers, the FinSix Dart [finsix.com] and Avogy Zolt [avogy.com], were said to use GaN transistors. The Dart still hasn't shipped, a year past its claimed release date. The Zolt has but is apparently using older Silicon Carbide-substrate transistors instead [chipworks.com] (Also see here [pointthepower.com].) (I received my Zolt recently and it is working well.)
It won't be a surprise to anyone following this technology that it can make inverters more efficient - that's what FinSix and Avogy have been claiming/demonstrating for two years at least.
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I work in RF, Ku band stuff, we use GaN parts like candy. One day I noticed that these things always come straight from Japan in hand-written and hand-packed little boxes... I asked what the BOM cost was and it was very high!
These things are so cutting-edge that you can't even google for the part number they ship you; it's not even on the manufacturer's page! You need to ask for the datasheet and often it's just screen printouts from the VNA...
I've also noticed that they smell different when the top explode
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GaN isn't cutting edge. It's just super expensive. The only real use for GaN, due to the cost, is in radio transmitters and a few other niches where they need the ability of GaN to run at faster MHZ than silicon can support and can afford to pay the ridiculous process costs. GaN will remain a niche in process tech until they can find a way to make chips cheaper and they've been trying for a very long time. A lot of companies have come and gone trying to improve GaN because of the promise.
I can remember in t
Re:GaN Transistors are the future (Score:4, Informative)
RF GaN parts are certainly expensive - the GaN is grown on silicon carbide substrates which is incredibly expensive by itself, and high-speed RF stuff has much more demanding fabrication needs like very small T-shaped gates, better contact resistances, and so on.
GaN for power electronics is much cheaper, grown on 6 inch silicon substrates, and produced in much higher volumes. You can buy GaN parts from EPC on Digikey for a couple of dollars each, the other GaN power device manufacturers aren't selling publicly that I know of (just to partners, or nobody) but the cost per unit is not tremendous - a bit more than the same voltage and current rating silicon device but the GaN part can switch faster.
Why is this important? (Score:2)
Genuine question. The web site talks about inverters being 1-2 cubic feet in size, and it wants them smaller. I understand that smaller is better. What's the application that requires a 2kW inverter smaller than that?
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Marine or other mobile applications?
2-5kw is a sweet spot for these applications. Most marine generators in recreational applications are about 5kw -- and most of that is usually to drive air conditioning or similar high voltage applications.
2kw or so, though, is pretty decent for off-battery use of lower powered items and might even provide enough power (if you can use all 2k) for a small microwave.
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Heck a 10,000 BTU AC unit in a small travel trailer only needs 700W once running so a 2kW setup would net you almost 3:1 runtime:collection (or about 2:1 once all inefficiencies are accounted for). The big problem is that 2kW of panels takes a lot more room than you have on a travel trailer (at least the ones that only need one 10k A/C!)
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Didn't know about the design goal wanting 400V DC input. That clearly cements it in some kind of fixed installation mode, but it would be interesting to know if the input voltage can be scaled down.
There are some interesting variable speed DC generators which seem to provide better overall efficiency than fixed-speed AC generators because they can run at lower RPMs when power demand is lower, but they mostly seem to make sense when integrated into a larger battery bank. And usually they have some kind of
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An obvious one for me is for solar cells. As small/flat as possible to minimize the size/mass of an array.
When I've looked at home arrays, the inverter is a large box that fits off to the side in its own enclosure. I can see that having a small inverter that is part of the array would be an advantage in terms of cost and installation workload.
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Yeah, but solar cells to generate 2 kW are large. The size of the inverter doesn't seem like a limiting factor in that kind of installation.
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You don't need to use the solar cells directly, you charge up your batteries from your solar panels, or from cheap off-peak grid power, and you then need an inverter so you can run all your AC appliances from the batteries. The basic Tesla Powerwall model is 3.3kW, so that should give you a pretty strong hint of at least one application.
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That helps. I don't foresee a lot of applications that have room for those batteries but not for the inverter though. I can definitely see the merit of the complaint that the inverter is too large compared to the batteries. I'd still like to know what makes it very important rather than just something that's nice to have. Maybe nice to have is an adequate motivation for Google ...?
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Matching inverters to an appliance would be my guess.
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That's the right question. I think you'll eventually reach the inevitable conclusion that we must hack their inverters, with the end result of filling the Google data center with freshly popped popcorn.
Trifecta (Score:4, Funny)
We may have just hit peak Google. Three stories in a row.
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Split phase (Score:5, Interesting)
Cubic inches? (Score:5, Insightful)
Cubic inches?! So this isn't a project intended to be looking beyond the borders of one country?
-Matt
Re:Cubic inches? (Score:4, Funny)
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>> A technology company such as Google (and a tech-focused website such as /.) should be trying to drag the rest of the country out of the dark ages, not perpetuate a backwards and harmful tradition.
Yep ! interesting fact is, NASA was working largely in metric at apollo times, and reverted to more imperial as far as i know....
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First of all, you mean two countries, right?
Second of all, by "one country" you mean "the most important and powerful country that has ever existed through all of history, including Rome". So, yeah, okay fine, not intended to be looked at beyond that country.
Also, if we are going to keep pretending that Europe is more than one country, then I insist that Europeans recognize the USA as fifty countries. Then, any time they complain that Americans don't know the King of whichever European theocracy, they can p
Re:Cubic inches? (Score:4, Funny)
>> Yea. Inches are kind of THE STANDARD for doing PCB layout worldwide.
Not any more.
Today, 80-90% of components are SMD, and SMD is metric.
The odd 2,54 component is just destroying the harmony of the grid, but that's OK, the modern CAD packages handle this well.
Yeah, sometimes I use 2,00mm headers instead of 2,54mm -> more compact, but a bit more exotic.
Farewell, imperial.....
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Cubic inches?! So this isn't a project intended to be looking beyond the borders of one country?
-Matt
It's a secret ploy to force all those millions of non-imperial-units-aware challengers to use Google:
https://www.google.com/search?... [google.com]
Someone call the antitrust department!
Economics of those challenges? (Score:2)
As a professional, I expect to be paid for the work I do for hire. Sure, some things are done for fun, but building entire product is rarely is... Like, look at the open source softw
How $1 million cost, for an inverter company? (Score:4, Insightful)
If you started with nothing and had to buy all of the tooling and equipment, recruit people, etc., I could see this easily costing $1 million, but the winner is an inverter company. They already have all of the tooling, equipment, expertise, etc.
They "just" needed to optimize one of their existing designs for size. Also, they only needed a working prototype, not a full production model. How do you figure that costs a million dollars?
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Google is not avoiding paying one team, but several. Not only are they avoiding dealing with exclusively a firm at random, who, lacking financial competition, is likely to build in a decent profit margin, but they're soliciting from several teams who understand the nature of the competition. Regardless, they're catching a price break. Successful companies often get that
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I suppose the publicity of winning is worth something, though maybe not as much as $1 million.
Does it? (Score:2)
"Google Challenge Results In Astoundingly Efficient Inverters"
Sooo, what is that number? I can't find it anywhere.
Commercial PV inverters are about 97% peak, 93% average. Not a lot of room for movement there.
Efficiency? (Score:2)
Watts per cubic inch (cm or whatever) is just one measure. It's a fine target for aerospace and automotive applications. But it is of secondary importance for fixed installations like solar. Here, the efficiency I'd be interested in is power conversion efficiency. Particularly across a wide range of loads. And I'd like that efficiency to come at a reasonable price as well. Where I can evaluate the dollars spent to save a Watt of inverter loss vs the dollars per Watt that a larger solar panel will cost me.
T
I'll believe it when ... (Score:3)
Re:AC is by its very nature inefficient (Score:5, Funny)
Is that you Thomas Edison?
Stop electrocuting elephants!
Re:AC is by its very nature inefficient (Score:4, Insightful)
If you don't understand why this isn't going to happen, you need to be kept away from grid design.
Replacing the AC network with a DC network would mean either replacing or substantially modifying the entire fleet of existing generation plant, all distribution and conversion equipment, all industrial equipment powered by electricity and most appliances. You might well be right that you can achieve better efficiency in a new network with DC than with AC; when you have to replace the entire electricity system, from spinning turbine to phone charger, it just ain't gunna happen.
Japan (Score:3)
Hell if I remember correctly half of Japan runs at 60Hz and the other have at 50Hz due to a standards change years ago, and they've never been able to convert even that due to the monumental effort required, and that is AC to AC!
Though I expect the use of things things would be for Cars and Homes, not entire network conversions...
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It's due to half the countries power plants using generators from US (GE), and the other half generators bought from Germany (AGE), originating back in the early power grid days when each city had it's own individual separate grid.
There are connections between the grid with frequency converters, but they don't have much capacity.
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Yeah it's hard. Hard as a rock :)
https://www.youtube.com/watch?... [youtube.com]
on a more related side, the solution the winner used is very innovative. switching a filtering capacitor with full power swing for minimizing the size is quite novel.
I love the MLCC bricking from team Augustin Reibel also
Re:AC is by its very nature inefficient (Score:4, Interesting)
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We should not be generating AC power in the first place. DC is much more efficient.
Perhaps not now, but way back when, AC was required because transformers could only work on AC, and people wanted high voltage, low current to minimize power wasted in the pylons' cables.
Ironic heading to the comment (Score:3)
Personally, I read it as "Anonymous Coward by its very nature inefficient".
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We should not be generating AC power in the first place. DC is much more efficient.
I look forward to your design that can convert generator output to 300kV DC for long distance transmission.
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Ten 30kV DC CRT power supplies wired in series, from discarded televisions. Recycle!
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Cock, alternating, cycles... I'm pretty sure there's a retort about how your dick hertz in there somewhere.
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Re:Who participated? (Score:5, Funny)
I think he forgot the /sarc at the end of his post.
You are assuming GP male. This kind of sexist assumption is exactly the type of thing that needs to be stamped out in the industry.
Now if you need me, I'll be in my safe space. /sarc
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I think someone is trying to be too politically correct. For ages it's been assumed that "he" and "man"/"mankind" may be used in a generic sense to refer to everyone, because English is already cumbersome enough as it is without having to write out "he or she" just to satisfy the hypersensitive knee-jerk reactionists out there.
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And when AIs start objecting we'd need to write she/he/it.
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I think that's the point - to remove some of the challenges not everyone else has so they have the opportunities everyone else does.
Whether any given program actually achieves that is of course debatable.
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Because registering a team is somehow hard for minorities or women? The fact they had to use the internet or english? Please describe a change faced by these groups that a white male from Appalachia would not also face?
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The original parent was obviously speaking with tongue-in-cheek to mock the whole concept and your reply while being modded as a troll was completely genuine.
You want the truth? People can't handle the truth!
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Thanks to all the AC for clarifying why Trump might become you president....
As a side note: positively discrimination on a goal oriented challenge would be beside the point, after all you want the maximum of "what ever" from the winner...
But not going through a phase of positive discrimination has two drawbacks, you get less talented people from the discriminated group, and you give the illusion to a whole bunch of idiots in the advantaged group that they are actually worth something in their chosen activit
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astounding posting stimulus (Score:2)
Google must have gotten Timmay a new wheelchair.
or wired the current one to give 240VAC shocks to the occupant.
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That's true, the extreme power density at the expense of cost and efficiency is kind of a niche thing, especially more with active air cooling, and grid connection, there's no point in that strange combination, really....
But this is to be considered research! The advances in this field can be applied to more common segments....