Well this comes as a big surprise. I just thought that he'd be taking a break. I also think that he wasn't forced to resign as much as he thought it'd be the best choice for the company (he probably has majority voter control).
Kalanick - because of his super competitive nature - was probably the best person to be CEO during the time he was but maybe its now time for a more matured and seasoned executive to take over. Just my thoughts.
More matured and seasoned executive? Kalanick is 40, has star experience like almost nobody in tech business... I'm wondering who would be more matured for highly unregulated, exploding industry that depends on innovation (solar, self-driving cars)?
With a new seasoned exec, I predict Uber will stabilize, IPO at some point and becomes the Yahoo of the industry. It won't be the next Google, Amazon or Facebook (all led by founder CEOs), that's for sure.
Not to be defending/advocating that uBeam's tech is actually any good, but the inverse square law refers to omnidirectional transmission, while uBeam's claims are related to directional transmission of power.
Have you ever seen an audio frequency transducer (say up to 200 KHz) that delivered an actual beam?
Usually the inverse square law is very much in effect when it comes to audio, this is because the medium (waves in air) behaves as water does with waves do in a pond rather than say the light coming out of a laser or any other focused source of electromagnetic radiation.
Distance from the transmitter will very much be a factor.
I wasn't saying it wa snot a factor, and I totally agree with you, but the inverse square law per its exact definition does not apply here.
I think uBeam is another Theranos, but granted at a much smaller scale. Still can't believe it has raised so much money and so much press without basic questions really being answered.
These people got 53% efficiency at 1 meter, which gives some hope for ultrasonic power transfer: Roes, M.G.L.; Hendrix, M.A.M.; Duarte, J.L., "Contactless energy transfer through air by means of ultrasound," IECON 2011 - 37th Annual Conference on IEEE Industrial Electronics Society , vol., no., pp.1238,1243, 7-10 Nov. 2011
Abstract: An alternative approach to the wireless transfer of energy is proposed, employing acoustic waves in air. Unlike conventional methods, acoustic energy transfer is able to achieve energy transfer at high efficiencies over distances that are large in comparison to the dimensions of the transmitter and the receiver. This paper gives an overview of the principle and explains the different loss mechanisms that come into play. A theoretically limit on the achievable efficiency is calculated. It exceeds that of a comparable inductively coupled system by an order of magnitude. First preliminary measurements indicate that AET is feasible, although the measured efficiency is lower than the predicted theoretical limit.
Ok, I read the paper. You got that completely wrong, the 53% is theoretical performance at 1 meter, the actual peak performance measured was 16% at an extremely small distance and two full orders of magnitude less (so 1%) at a distance of 100 mm.
The maximum output they measured was 37 uW, so 1000 of these would output ~37 mW, with an input power 1000's of times higher.
If anything this paper is a nice example of how theory and practice differ. It also highlights another big loss factor for ultrasound power transmission, the angle of incidence, the power falls of as the co-sine of the angle between the transmitter and the receiver (maximum at 0 degrees, minimum at 90 degrees).
Grr. I can't access that paper but thank you for digging that up. If Animats' calculations above are accurate though then uBeam is at a very small fraction of that 53%.
Is there anything in that paper that could explain the difference?
If you make a free account at deepdyve.com, you can read a free online preview of the paper for 5 minutes. The paper is only six pages long so that might be enough time to find an answer the question. (Or enough time to take six screenshots...).
I don't know any more because that was how I found that and skimmed the paper about three years ago, for a prior discussion of uBeam here on HN.
Yes, I mentioned phased arrays in my earlier comment. Even so that's a lot less focused than what you might believe it does, it's more like a directional wavefront than a focused beam. So you'll still lose lots of power due to the expanding wavefront (conveniently left out of the wikipedia drawings but I can see why they did that).
Back when my dad still worked at Aberdeen University, they had a phased array of maybe 7 or 8 transducers of about 8 cm each, that at a range of 6 inches or so, could deliver a focused beam that would penetrate a phantom / lab animal enough to cook a 2 - 3 cm sphere several cm below the skin.
The research was aimed at basically heating carcinomas above the 44 oC needed to kill the cells.
So you can focus an ultrasound beam, but it seems like a heck of a way to charge a phone.
If you pump enough energy into the source, sure. But your average coffeeshop is not going to replace their ceilingtiles with what would be really inefficient space heaters in order to charge some phones (and cook the inhabitants in the process).
That's the whole point of the exercise here: if the efficiency isn't there the whole thing is dead because you can't be pumping kilowatts into space in order to get a few watts (or milliwatts) back out. The difference between the two will get converted into heat!
So the only way this will work is if the efficiency is really high, much higher than seems to be feasible right now.
> they're cheaper because they can subsidize their
fares via VC money
That's not the (only) reason why they're cheaper.
They're cheaper because they offer drivers less downtime, therefore the drivers can end up earning more money since they're driving more of the time and earning fares.
They're also cheaper because services like uber pool and lyft line allow riders to spilt the fare among themselves.
I also think that Uber and Lyft will be cheaper than taxis for many more years to come. They're just more efficient as business models than taxis'.
What we would rather see succeed really has nothing to do with what will ultimately succeed. In the end, every developer will choose what they want based on ease of use, their preferences, features, etc. The most elegant technology is not always the one that "wins" - it's the one that most people choose to use (for whatever reason) and contribute to.
The issue for me isn't performance as in speed but performance as in battery life. Chrome, and hence any electron app, by far uses the most energy on my laptop.
Maybe one part of the problem is conflating laptops with "desktop". Maybe I'm misguided since I don't use laptops for serious screen time and thus don't really care about power consumption at all, but it seems to me that perhaps laptops shouldn't be lumped in with desktops in this way as is now popular. Maybe we still have 3 major form-factor platforms[1], or perhaps even laptops should rather be lumped in with mobile, especially since we have 2-in-1 tablet/laptop hybrid devices.
[1]: Contrary to what Intel has been pushing with their lamentable "mobile-first" strategy.
You're going to be more and more in the minority on this. Even though I prefer Chrome, on my MacBook I use Safari because I find it's battery usage to be significantly less.
I don't notice anything similar with VSCode, so its not Chrome/electron implicitly.
They are x86 systems that run the same operating systems as big desktop towers. Many people use laptops as their one and only x86 machine. Why would you not lump them in with desktops?
I thought that was rather clear. Because they (partially) run on batteries. After all, that seems to be the main problem people have with Electron in these HN threads.
> So sell the gold and buy bitcoins... :-) (JOKE!)
Haha
On a more serious note, I think that bitcoin is a bit too expensive right now. It seems to have been pushed up from demand from China [0] some time ago, but I seems that the Chinese government tried to stop it [1]. I don't know where demand right now is from, though.
I'd be remiss if I didn't say also that it's amazing that bitcoin is something that is much less associated with criminals and the dark economy as it was in the past and is now being popularly used for some really noble things. Same for blockchain.
> those loans are scary
Yeah, they had better IPO soon.
I don't know for sure why they went with such onerous terms but I think that they thought they were growing fast enough and would IPO this year. It turns out that that won't be the case [0], since they still have some deals to make with record labels and others. They have Apple on their heels. I like Spotify a lot but I don't think there prospects are good.
I thought that they'd price a little lower than this ($14-$15) but it seems that the market (1) doesn't care too much about not having a vote or (2) has lots of faith in Snap management.
It'll be interesting to see how this plays out over the next 6 months.
Hugging Face Demo: https://huggingface.co/spaces/mosaicml/mpt-7b-storywriter