Okay, so once you've flipped over the sack of groceries in the back seat with g-force and your kid in his car seat is crying because you jarred him. Has the novelty worn off?
For the most part, the car's price tag will keep it out of the hands of adolescent jerks*. One remarkable aspect of electric cars is that the torque is much more easily controlled than with an ICE. The car can be a pussycat with the accelerator at halfway and an amphetamine crazed tiger at full power. Also, Tesla has a button that selects between "Sport" or "Ludicrous" (or is it "Insane") acceleration modes. Hint: Use sport mode when driving kids home from the grocery.
You also just used a couple miles of your battery's energy. Hope it was 'cool' for you.
Get with the times -- we are not talking about gasoline power here. My electric car's energy usage per mile is highly dependent on drag and angle of climb, but does not change significantly whether I accelerate slowly or at full speed.
* Some of us are middle aged jerks. Oh, and the kid absolutely loves the acceleration of my car (BMW i3), which was good enough to break a motor mount (upgraded under warranty).
Energy storage is proportional to voltage squared at constant capicatance? Really??? So if I connect two (super)capacitors in series, thereby doubling the voltage limit, I have somehow squared the energy storage! I don't think so!!!
Power goes up with voltage squared in resistive circuits, but that's a different issue. In this case, you'd get that power for a shorter time.
The algorithms at risk to quantum computing attacks (RSA, etc.) are essentially used just for key exchange. Unless you have an offline channel, you need these to communicate your one-time pad. Besides which, when using a one-time pad, the parties have to store it in at least two places before use, greatly increasing the time that these precious bits are at risk of being leaked or stolen.
Once key exchange has been accomplished, modern protocols rely on block or stream ciphers, which are not known to be vulnerable to QC attack.
Unless the levelized price for renewable generation drops substantially below that of coal, I don't see how this will "spur renewable energy adoption" except for regions where electricity prices are substantially higher (e.g. Hawaii, $0.30/kWh)
Excellent point. Now... where can I get a 100 mile long extension cord for my electric car?
How are batteries of environmentally friendly and sustainable?
Batteries are an enabling technology that can store intermittently available renewable energy for convenient use. Think wind powered cars and solar street lights, both can be made practical through the use of battery storage.
"Lipo" (lithium-polymer) batteries are subject to thermal runaway (exploding into flame) if abused. Plus they can be more vulnerable for reasons including the typically soft packaging (OTOH, cell phones are not often bursting into flames in people's pockets). Maybe you were thinking of lithium iron phosphate (LiFePO4) batteries, which have lower voltage and lower specific energy density, but are more robust?
In any case, I thought *we* were discussing all sorts of batteries here, including a variety of lithium chemistries.
Utility of a 2.8 second 0-60 time for most ICE car owners = 0.
Utility of being able to drive 500 miles and then 'recharge' in five minutes = lots.
Utility of having decent range and never having to stop at a gas station = priceless!
Seriously. Buy a second car (owners of this Tesla can certainly afford one). Or borrow a friends (they'll be happy to drive you Telsa for a day). Or rent a car for your trip. The convenience of having a fully charged car every morning more than makes up for any range anxiety I might have had, and my electric has less than half the range of a Tesla.
The claim that building this car generates 1/3 the emissions of a comparable battery electric vehicle is believable. The lie is that the majority of lifetime emissions are generated during vehicle manufacture. In the real world, BEVs look much better.
Agreed - except that Diffie-Hellman relies on the difficulty of solving the discrete log problem, not integer factorization - so that only RSA is vulnerable here, and only if bit-wise close primes were chosen for the key.
There's always the Mac Pro: Small; built to be hammered with ridiculous workloads; extremely quiet; and comes with that lovely trash-can-sleek styling. We play Windows games on mine using a Parallel's Virtual machine, but you'll want to boot directly to your game's OS for best results.
The price isn't pretty, but nobody said marriage is cheap.
"Almost Impossible" can be made very precise. Indeed, modern cryptography is based on the understanding that certain algorithms are "almost impossible" to reverse. Cryptographers prove theorems with wording like "indistinguishable from random by any polynomial time algorithm" when they mean almost impossible. So, Apple may be quite correct in their statement.
My take on this is that Apple likely has received legal orders it can not disclose, and implementing real, strong security to protect user's data.
Modern type safe languages have a lot going for them, but they don't solve the hard problems of concurrency. (n.b. purely functional languages allow easy parallelization of some mathematical functions, but do not solve the hard problem, either). Highly efficient threading, especially at the system level, is not made easier by type safety.
This instruction set extension offers transactional memory access, so a thread can begin speculative execution that modifies a block of memory, and roll back on a conflict, rather than stalling on a semaphore lock.
If you look around, you can find eye surgeons performing corneal collagen cross-linking in the US. My doc works in Colorado. The basic idea is that the combination of riboflavin (vitamin B2) and UV light causes the corneal layers to bond more tightly to teach other. The stiffer cornea is likely to maintain a better shape, but the main advertised benefit is stabilization, preventing worsening of the keratoconus.
In my case, laser ablation was used to remove the corneal epithelium (outer layer of cells) so the riboflavin eye drops would more readily diffuse into the cornea. I was a good candidate for the procedure, with a relatively thick cornea, and the outcome was good. The experience was a also a lot more painful than I expected, but worth the suffering. My eyesight is now OK (neither terrible nor great), and I can now consider Lasik if I want.
Of course, Intacs (small rings inserted into the eye that circle -- and help shape -- the cornea) are FDA approved for keratoconus, but the approval is under a Humanitarian Device Exemption, meaning they have not been proven effective.
OK. Now you are just plain wrong. Please read about car suspensions. You can start with the wikipedia article on camber angle: "The inside edge of the contact patch would begin to lift off of the ground if the tire had zero camber, reducing the area of the contact patch. This effect is compensated for by applying negative camber, maximizing the contact patch area." [Wikipedia]
I stated the fact that many suspensions attain desirable negative camber while turning as a consequence of body roll. That cars are set up for neutral camber when driving straight is not at issue. The interesing part is that this Mercedes rolls the opposite way, and I wonder what changes were made to suspension geometry to account for this.
On the contrary, body roll is, in my admittedly subjective experience, quite noticeable. I drive two cars, a typical family car and a sporty two seater. The difference is night and day. One can easily feel the family car "sway" into and out of turns.
Cars can gain traction in turns if body roll results in negative tire camber (especially on the outside wheel). I wonder if Mercedes has engineered a sort of reversed suspension to take advantage of this property. Or is that what they mean when they say the design is "not... for increasing cornering speeds"?
200 steps per rotation is normal for motors. However, the drivers everyone is using do 16x microstepping, good for 3200 steps per revolution. Accurate steps per revolution. That's better then 4096 +- 2 steps.
No, those motors are not good for 3200 accurate steps/rev: Motor accuracy here is likely to be +/-5% (10% range), so ideal accuracy will be closer to 2000 steps/rev, but real world accuracy drops with increased microstepping resolution due to varying load and detent torques, stiction, etc.
The good news is that this level of motor accuracy is irrelevant here. All you really need to do is beat the required positioning resolution (likely on the order of a few mils). A 20tpi lead screw and 200 step/rev motor easily beat this without microstepping. You probably still want a microstepping driver, though, since it can prevent mid-band resonance in addition to other features.
"Whoever... knowingly and with intent to defraud, accesses a protected computer... exceeds authorized access, and by means of such conduct furthers the intended fraud and obtains anything of value... shall be punished..." - CFAA (18 USC 1030).
That's what. (Disclaimer: IANAL and therefore don't know what I am talking about).
The synopsis completely misses the qualification, made in the first sentence, that TFA is discussing "concurrency, parallelism (manycore), and, of course, Big Data". Purely functional programming eliminates some significant issues in this type of programming (while introducing its own set of limitations). Meijer's point is that mostly functional programming is not really better than imperative here
For other types of programming, mostly functional style (using multi-paradigm languages) can be very nice. At least that's my position.
F# and C# are both multi-paradigm languages, and are both built on top of the CLR type system. Functional style is more natural in F#, but C# has first class functions (and lambda), too. F# has loops and assignment, but nothing as powerful/abuse-inviting as the C-style for loop. Neither approach is the one true style.
If you believe the proverb, "library design is language design" [from Bell Labs? Was it Stroustrup?], then F# is a much different language from other ML variants as it has native access to Dot Net/Mono libraries.
According to this, the difference in the US is that recreational model aircraft are covered by FAA Advisory Circular (AC) 91-57, while Unmanned Aerial Systems require either a Certificate of Waiver or Authorization (COA) or Special Airworthiness Certificate in the Experimental Category (SAC-EC). Operation in restricted airspace is another matter. In all cases, a pilot in command must maintain control of the aircraft (which I take to mean line of sight is required).
The other agency US unmanned aerial systems (UAS) have to contend with is the FCC. There are frequencies available for recreational RC use, and amateur radio bands, but last time I checked there was nothing for controlling a commercial UAS.
Slashdot Mirror
Okay, so once you've flipped over the sack of groceries in the back seat with g-force and your kid in his car seat is crying because you jarred him. Has the novelty worn off?
For the most part, the car's price tag will keep it out of the hands of adolescent jerks*. One remarkable aspect of electric cars is that the torque is much more easily controlled than with an ICE. The car can be a pussycat with the accelerator at halfway and an amphetamine crazed tiger at full power. Also, Tesla has a button that selects between "Sport" or "Ludicrous" (or is it "Insane") acceleration modes. Hint: Use sport mode when driving kids home from the grocery.
You also just used a couple miles of your battery's energy. Hope it was 'cool' for you.
Get with the times -- we are not talking about gasoline power here. My electric car's energy usage per mile is highly dependent on drag and angle of climb, but does not change significantly whether I accelerate slowly or at full speed.
* Some of us are middle aged jerks. Oh, and the kid absolutely loves the acceleration of my car (BMW i3), which was good enough to break a motor mount (upgraded under warranty).
Energy storage is proportional to voltage squared at constant capicatance? Really??? So if I connect two (super)capacitors in series, thereby doubling the voltage limit, I have somehow squared the energy storage! I don't think so!!!
Power goes up with voltage squared in resistive circuits, but that's a different issue. In this case, you'd get that power for a shorter time.
The algorithms at risk to quantum computing attacks (RSA, etc.) are essentially used just for key exchange. Unless you have an offline channel, you need these to communicate your one-time pad. Besides which, when using a one-time pad, the parties have to store it in at least two places before use, greatly increasing the time that these precious bits are at risk of being leaked or stolen.
Once key exchange has been accomplished, modern protocols rely on block or stream ciphers, which are not known to be vulnerable to QC attack.
Unless the levelized price for renewable generation drops substantially below that of coal, I don't see how this will "spur renewable energy adoption" except for regions where electricity prices are substantially higher (e.g. Hawaii, $0.30/kWh)
Excellent point. Now... where can I get a 100 mile long extension cord for my electric car?
How are batteries of environmentally friendly and sustainable?
Batteries are an enabling technology that can store intermittently available renewable energy for convenient use. Think wind powered cars and solar street lights, both can be made practical through the use of battery storage.
Uh... no.
"Lipo" (lithium-polymer) batteries are subject to thermal runaway (exploding into flame) if abused. Plus they can be more vulnerable for reasons including the typically soft packaging (OTOH, cell phones are not often bursting into flames in people's pockets). Maybe you were thinking of lithium iron phosphate (LiFePO4) batteries, which have lower voltage and lower specific energy density, but are more robust?
In any case, I thought *we* were discussing all sorts of batteries here, including a variety of lithium chemistries.
Utility of a 2.8 second 0-60 time for most ICE car owners = 0.
Utility of being able to drive 500 miles and then 'recharge' in five minutes = lots.
Utility of having decent range and never having to stop at a gas station = priceless!
Seriously. Buy a second car (owners of this Tesla can certainly afford one). Or borrow a friends (they'll be happy to drive you Telsa for a day). Or rent a car for your trip. The convenience of having a fully charged car every morning more than makes up for any range anxiety I might have had, and my electric has less than half the range of a Tesla.
The claim that building this car generates 1/3 the emissions of a comparable battery electric vehicle is believable. The lie is that the majority of lifetime emissions are generated during vehicle manufacture. In the real world, BEVs look much better.
Recycling exhaust is not new. BMW calls their system Turbosteamer,
Agreed - except that Diffie-Hellman relies on the difficulty of solving the discrete log problem, not integer factorization - so that only RSA is vulnerable here, and only if bit-wise close primes were chosen for the key.
There's always the Mac Pro: Small; built to be hammered with ridiculous workloads; extremely quiet; and comes with that lovely trash-can-sleek styling. We play Windows games on mine using a Parallel's Virtual machine, but you'll want to boot directly to your game's OS for best results.
The price isn't pretty, but nobody said marriage is cheap.
"Almost Impossible" can be made very precise. Indeed, modern cryptography is based on the understanding that certain algorithms are "almost impossible" to reverse. Cryptographers prove theorems with wording like "indistinguishable from random by any polynomial time algorithm" when they mean almost impossible. So, Apple may be quite correct in their statement.
My take on this is that Apple likely has received legal orders it can not disclose, and implementing real, strong security to protect user's data.
"Good afternoon, Officer. My time is valuable. Your time is valuable. Please don't waste time by asking questions I am not required to answer."
"Sir, Have you been drinking?"
"Am I required to answer that question?"
"No."
"Please stop wasting time. As I said, my time is valuable. Am I free to go now?"
etc.
Here's what the US National Academies have to say: "One might think that airplanes, trains, and buses would consume most of the energy used in this sector but, in fact, their percentages are relatively small--about 9% for aircraft and about 3% for trains and buses. Personal vehicles, on the other hand, consume more than 60% of the energy used for transportation."
Completely eliminating emissions from buses would make only a small difference in the big energy picture.
That said, electric buses might not be such a bad thing. I'm driving an electric car these days and it is awesome (even if it isn't a Tesla).
Modern type safe languages have a lot going for them, but they don't solve the hard problems of concurrency. (n.b. purely functional languages allow easy parallelization of some mathematical functions, but do not solve the hard problem, either). Highly efficient threading, especially at the system level, is not made easier by type safety.
This instruction set extension offers transactional memory access, so a thread can begin speculative execution that modifies a block of memory, and roll back on a conflict, rather than stalling on a semaphore lock.
If you look around, you can find eye surgeons performing corneal collagen cross-linking in the US. My doc works in Colorado. The basic idea is that the combination of riboflavin (vitamin B2) and UV light causes the corneal layers to bond more tightly to teach other. The stiffer cornea is likely to maintain a better shape, but the main advertised benefit is stabilization, preventing worsening of the keratoconus.
In my case, laser ablation was used to remove the corneal epithelium (outer layer of cells) so the riboflavin eye drops would more readily diffuse into the cornea. I was a good candidate for the procedure, with a relatively thick cornea, and the outcome was good. The experience was a also a lot more painful than I expected, but worth the suffering. My eyesight is now OK (neither terrible nor great), and I can now consider Lasik if I want.
Of course, Intacs (small rings inserted into the eye that circle -- and help shape -- the cornea) are FDA approved for keratoconus, but the approval is under a Humanitarian Device Exemption, meaning they have not been proven effective.
OK. Now you are just plain wrong. Please read about car suspensions. You can start with the wikipedia article on camber angle: "The inside edge of the contact patch would begin to lift off of the ground if the tire had zero camber, reducing the area of the contact patch. This effect is compensated for by applying negative camber, maximizing the contact patch area." [Wikipedia]
[Please read comments carefully before posting.]
I stated the fact that many suspensions attain desirable negative camber while turning as a consequence of body roll. That cars are set up for neutral camber when driving straight is not at issue. The interesing part is that this Mercedes rolls the opposite way, and I wonder what changes were made to suspension geometry to account for this.
On the contrary, body roll is, in my admittedly subjective experience, quite noticeable. I drive two cars, a typical family car and a sporty two seater. The difference is night and day. One can easily feel the family car "sway" into and out of turns.
Cars can gain traction in turns if body roll results in negative tire camber (especially on the outside wheel). I wonder if Mercedes has engineered a sort of reversed suspension to take advantage of this property. Or is that what they mean when they say the design is "not ... for increasing cornering speeds"?
200 steps per rotation is normal for motors. However, the drivers everyone is using do 16x microstepping, good for 3200 steps per revolution. Accurate steps per revolution. That's better then 4096 +- 2 steps.
No, those motors are not good for 3200 accurate steps/rev: Motor accuracy here is likely to be +/-5% (10% range), so ideal accuracy will be closer to 2000 steps/rev, but real world accuracy drops with increased microstepping resolution due to varying load and detent torques, stiction, etc.
The good news is that this level of motor accuracy is irrelevant here. All you really need to do is beat the required positioning resolution (likely on the order of a few mils). A 20tpi lead screw and 200 step/rev motor easily beat this without microstepping. You probably still want a microstepping driver, though, since it can prevent mid-band resonance in addition to other features.
What's illegal about it?
"Whoever ... knowingly and with intent to defraud, accesses a protected computer ... exceeds authorized access, and by means of such conduct furthers the intended fraud and obtains anything of value ... shall be punished ..." - CFAA (18 USC 1030).
That's what. (Disclaimer: IANAL and therefore don't know what I am talking about).
The synopsis completely misses the qualification, made in the first sentence, that TFA is discussing "concurrency, parallelism (manycore), and, of course, Big Data". Purely functional programming eliminates some significant issues in this type of programming (while introducing its own set of limitations). Meijer's point is that mostly functional programming is not really better than imperative here
For other types of programming, mostly functional style (using multi-paradigm languages) can be very nice. At least that's my position.
What would constitute the "engine timing" on an all electric car?
Timing in this case would be the phase of the variable frequency drive that powers the motor.
F# and C# are both multi-paradigm languages, and are both built on top of the CLR type system. Functional style is more natural in F#, but C# has first class functions (and lambda), too. F# has loops and assignment, but nothing as powerful/abuse-inviting as the C-style for loop. Neither approach is the one true style.
If you believe the proverb, "library design is language design" [from Bell Labs? Was it Stroustrup?], then F# is a much different language from other ML variants as it has native access to Dot Net/Mono libraries.
According to this, the difference in the US is that recreational model aircraft are covered by FAA Advisory Circular (AC) 91-57, while Unmanned Aerial Systems require either a Certificate of Waiver or Authorization (COA) or Special Airworthiness Certificate in the Experimental Category (SAC-EC). Operation in restricted airspace is another matter. In all cases, a pilot in command must maintain control of the aircraft (which I take to mean line of sight is required).
The other agency US unmanned aerial systems (UAS) have to contend with is the FCC. There are frequencies available for recreational RC use, and amateur radio bands, but last time I checked there was nothing for controlling a commercial UAS.