Everytime an electron passes from the metal interconnect to silicon in a semiconductor a quantum process is occuring. The electron has to pass a thin but but carrier empty region by quantum tunnelling because the metal either fills or empties the region of the interface. So the electron has to do a "quantum jump" so to speak. So basically every semiconductor is quantum to a degree and in an instrinic way.
Although everything has a quantum component when it is small (because quantum=physics and everything has to follow the laws of physics), this "tunnelling" aspect isn't really important part of the function of the IGFET as it is currently used.
Sure, with a metal/semi-conductor interface, there is a "depletion-region" which creates a potential barrier that needs to be overcome by electrons. As I understand it, the potential provided by the power-rails to switch the device are more than enough to overcome this potential barrier so this pretty much looks like an resistive (ohmic) contact and the tunnelling isn't an intrinsic part of the operation. This "depletion-region" is mostly interesting as a function of reduced switching speed and limitation of the saturation current through the channel causing more leakage in static operation (the "bad" stuff).
If we didn't provide enough potential by the power-rails to cross this potential barrier of the depletion region formed by a metal-semiconductor junction, then any charge that wanted to cross it would have to tunnel and that would be an intrinsic part of the operation of the device. The tunnelling current would be very small relative to the larger currents provided by the power-rails that are in common use today and would result in really slow transistors.
For the record - in flash memory what people refer to as 'tunnelling' might better be referred to as "electrical breakdown of a dielectric"... People can call it tunnelling if they want to - but ask me this - if it is tunnelling and not electric breakdown (in the old fashioned classical sense) why are write cycles limited?? I know which of those two phenonoma damages materials in the long run - and it isn;t tunnelling..
In actuality, physics is always involved, so since a flash memory is an actual device, rather than a theoretical device, both processs are happening , but my understanding is that di-electric breakdown isn't currently the predominant process.
The difference between di-electric breakdown and tunnelling is that di-electric breakdown creates semi-permanent electrically conductive paths through the insulator where tunnelling does not, but statistically leaves some charge trapped in the insulator. The primary limitation of cells on current flash processes are oxide degradation due to the accumulation of **trapped charge** reducing the F-N tunnelling efficiency and also impairing the action of the control gate. In contrast di-electric breakdown will over time increase the amount of **charge leakage** through the insulator and will eventually make it difficult for the cell to retain information, but on current proceseses, that effect is smaller than the charge trapping issue.
FWIW, There has been some effort to try to develop a way re-anneal the oxide to reduce/eliminate the trapped charge issue (e.g., by locally heating it), so eventually that make the di-electric breakdown process the limiting factor, but that is still a bit researchy...
Is it really necessary to have the same number of qubit as the problem, tho?
Unfortunately, I think it's worse than that.
The "quantum" part of Shor's algorithm factoring N involves a period finding operation that requires an input and output of k-qubits where k is approximately 2logN+1. A simplistic implementation to factor a 2048-bit number would be minimally 2x2048+1 input and the same number of output so about 8194 qubits (I don't think you can share the input and output for the quantum fourier transform computation step). That also presupposes that you can change the circuit connecting these qubits into N configurations check each. We've got a long way to go before we are quantum factoring...
Transistors directly use quantum effects to work, yet we don't call desktop computers "quantum computers".
The transistors in the CPU in your desktop computer are IGFETs (insulated gate field effect transistors). The principle of operation of this device is that moving charge on the gate can enhance or deplete the number of mobile electrons in the source to drain channel under the gate and cause it to turn on or off using an electric field effect which is not considered a quantum effect.
To be fair, at the scales that modern transistors operate, there are some interesting quantum effects. Most are considered as "bad" (causing problems with the "classical" operation of the transistor by tunneling charge or changing thresholds), but there are a few things like strained silicon that are used to improve performance (which used to create quantum containment and effective mass modifications to make small geometry operation more feasible), but these quantum effects aren't intrinsic to the operation of a generic IGFET (just a FET that's really small).
There are of course stuff in your desktop computer that intrinsically rely on quantum effects to work. For example, the flash memory (uses tunneling to move charge in and out of an isolated control gate). However, there are many other things that are similar to the transistor's use of QM effects like the optical drive (solid state laser uses bandgaps to get a certain frequency) and the disc drive (uses the GMR effect which is related to QM electron spin transport), but that's really just to make stuff work when it is really small, not intrinsic to the operation.
In the end, it's all physics and computers use physics and when you make things really small the quantum nature of physics must be accounted for, but it can be taken advantage of too. As for calling a quantum adiabatic computer a "quantum computer" I agree that would be a no. It technically relies on tunneling, so it's sort of like a flash memory in that respect (it's basic theory of operation requires a non-classical QM effect which is different than a transistor).
As to whether D-Wave actually does or doesn't implement a QM adiabatic algorithm, or perhaps just uses QM tunneling to improve a more classical annealing implementation speed and result, and if that actually makes any practical difference, is another question.
It is decidable, but some cases are exponentially hard to decide (and the Logic Equivalence Checking or LEC tools will barf).
Quick background. The task of converting a logical representation of a chip function to a physical representation is a very time consuming process, so often if a bug is found or a timing problem is found, you don't want to restart the process, but instead you probaly to make a small local change (equivalent to patching a binary to fix bug rather than recompiling). But when you create that patch, how do you know that it does what you want?
That's why they make LEC tools (like Formality). If you made a timing/retiming fix, you can be assured it doesn't change the functionality, if you made a small bug fix, you can fix the source code run your tests and know that the results apply to the patched version as well.
If you tried to run LEC tools on a whole chip, it would generally barf. You generally have to run it on small blocks of the chip and build up your equivalence check for the whole thing hierarchically.
LEC tools run in a reasonable computing resource configuration because big chunks of the design are exactly the same and the primitive binary operations in IC design have simple to define properties that have easy to describe using efficient structures like ROBDDs. If you tried to take this approach on typical software executable, you would likely quickly find that either there is no efficient data structure to evaluate equivalence, or that the primitives that are reasonably efficient don't have simple to define properties (e.g, FP math is not associative, deltas in non-live/don't care parameters/registers/stack-values).
Instead of a membrane matching the impedence of a "meta-material" made by punching regularly spaces in a wall (kind of like a meta-material drum), the UT-austin work describe holes made with a "meta-material" approach. Basically a hole with some transverse tubes cut a regular intervals to create resonances that change the effective impedance parameters allowing pretty much lossless transmission through the hole (kind of like a meta-material horn).
Although MSFT claimed to lock down WinRT to force developers to target Metro so there would be lots of tablet friendly apps instead of win32 ports, my theories as to why MSFT really decided to have a locked down WinRT...
1. They are mostly using WinRT as a lever against Intel to get them to reduce the margins on x86 chips so that they can compete against android in the low-end tablet space w/ x86 chips. If this strategy is successful and intel capitulates, they didn't want too many consumer WinRT ARM win32 binaries floating in the wild to support as they drop support for ARM. 2. They wanted to sell unlocked versions to enterprises at a higher price. 3. Available ARM SOCs are 32-bit and the GPUs don't yet have universal support for DX10 (the minimum required for win8) and they don't want developers to go back a generation to the lowest common denominator just to pickup WinRT compatibility as that would undermine the upgrade cycle component of their business. 4. They didn't want to support malware/anti-virus on ARM (maybe because of $$$ supporting too many platforms or maybe slow performance on ARM).
All these reasons could change in the future, but they were probably important during the original launch (and thus they flipped the flag to lock it down).
As a non-physicist, my understanding of the Higgs mechanism is pretty weak, but...
The way I understand it the generic idea of the Higgs mechanism isn't simply restricted to be a "mass-generating" mechanism, although the most interesting Higgs mechanism that are searched for are the ones that can suggest electro-weak symmetry breaking which gives non-zero rest masses to W and Z bosons. The reason why most folks are searching for something that can describe this is that W and Z boson have the largest masses (~85x a proton) whereas a simplistic assumption of symmetry in the electric and weak fields would imply that these particles have zero-mass.
The generic Higgs mechanims pre-supposes a field (which exists everywhere there is the effect). Simplistic assumptions of convervation properties of the field manifest themselves as certain symmetries (which imply other symmetries and can be put into a mathematical framework similar to gauge groups, but that's not too important). The question becomes since the classical equations describe a mass-like scalar term that seems to be independent of the gradients and couples to these fields, how can we put a mass-like term into a framework with all these symmetries, yet be have it be non-zero?
The basic idea is that the field must have some sort of symmetry-breaking. At some high-energy (or temperature or potential), the expected value of the mass-like term averages out to zero, but as you go towards low-energy (or temperature, or potential), the expected value becomes non-zero yielding a mass-like term. As it turns out, if the potential of the field is shaped like a W or a sombrero, it can have this property. At high potential (when you can't see the "hat" part), the expection is symmetric around zero and the field has the required symmetry. As the potential goes down (including all the way to zero), the low-energy expectation value falls away from zero (at a consistent radius away from the center because of the "hat"). This is apparently called spontaneous symmetry breaking.
Why would the field potential have this shape? Who knows? But if it does, it can simultaeously satisfy the symmetries and still have a gradient/direction independent expected value term (which would act just like a scalar constant just like mass in all the classical physics formulas).
So what everyone is calling the Higgs field (and higgs particle) are mostly a specific interaction that describes how the W and Z boson can appear to have a non-zero mass-like term with electro-weak symmetry breaking. It is my understanding that it is currently just assumed that all other stuff that has non-zero mass would be similar, but it doesn't really explain what people think of as mass per-se (which has a mysterious gravitational equivalence), it just gives a explanation for the observations that are likely consistent with mass in terms of energy of the various fields (other than gravity).
VP9 will be completely open. Just remember that creating video codecs is very complex process on its own, so adding things like encryption schemes will likely require a bunch of professional engineers.
I'm not sure what to take away from that statement about "professional engineers".
It seem like you implying that since VP9 didn't want/need "the community" (of presuably unprofessional folk) in its development that somehow the current developers of VP9 don't feel that "the community" can develop an encryption schemes (being the unprofessional folk we are)?
I gather that the Cathederal mechanism of development might be deemed necessary (by google) to avoid IP contamination of VP9, but as someone that does stuff in this area (video compression and encryption) professionally, what you seem to be implying is a bit condecending to "the community" of open source developers (many of whom are professional engineers in our day-jobs)...
In fact, I might argue that encryption schemes are best done in the community (e.g., like the AES and the SHA-3 process) because an open competitive environment is the best way to assure the actual difficulty of cirvumenting the scheme is known (rather than assuming that some experts have it figured out).
Among the additions this year are a 3-D printer, a Frisbee-throwing robot made by students at Aragon High School, and a "reverse-engineering" exhibit where kids can take apart VCRs and computers to see how they work. Colaluca also has organized competitions in coding and app-making, and he deputized employees of local computer companies to judge them.
Because there happens to already be a cheap way of amplifying a small sample of DNA for identification (PCR). Most other easy to manufacture serializable microscopic substances mostly suffer from dillution/detection problems.
The technique is to use junk DNA encoded with a serial number. DNA are the is the microscopic grains and PCR is the way to quickly do the detection if a specific serial number is present (although PCR isn't yet as simple as a swab).
Presumably you could spend years doing revolutionary nobel prize winning research and replace DNA with another chemical that had an even cheaper way of detection for this niche application, but someone who worked for Applied DNA Sciences might instead think about just using DNA and an existing nobel prize winning PCR test and get something to market faster.... Just say'n...;^)
the plane airbus did not want to build at the time, as they just blew up their budget on the A380 delay
FTFY...
Basically, Airbus's parent company (EADS) simply didn't want to invest that much of their own money on a new development and wanted to pressure the european governments into some sort of financing trick***. That didn't happen, so EADS reluctantly spent their own money on A350XWB development (and basically they have been mostly cash-flow negative since then which really puts a crimp on the value of the executive's stock options).
*** it's a bit complicated, but because of the WTO dispute with Boeing, the government can't really just give or loan the money to EADS for new development w/o triggering potentially expensive trade retaliation, but governments can loan money for something called "launch-aid" (temporary funding *after* development to finance inventory and supply chain buildup). It's always a bit suspicious when "launch-aid" loans happen before the development even starts (which seems to frequently happen with Airbus as they use the uncertaintly of location of jobs as enticements)...
record=chromosome song=the DNA in some specific person's chromosome chord=mutated BRCA gene diamond stylus=the cDNA technique to read DNA laser pickup=some new way to read DNA
AFAIK the decision was that the "chord" is not patentable, because it's part of the naturally occurring "song". However, since the current method to find if the "chord" is present in the "song" uses a "diamond stylus" pickup to read the "record" and is described in a patent, it might be patentable (they didn't address this in the ruling the issue of obviousness) since it uses a method to read the "song" which isn't a natural process. SCOTUS simply upheld the patent (it still can be re-examined).
The inference I made is that if someone else comes up with another way to detect the "chord" in the "song" that doesn't use a "diamond stylus" (say a "laser pickup" mechanism, or taking a picture of the groves on the record and having a computer recreate the audio), then the current patent is totally circumvented because SCOTUS says that it is not possible to patent nearly all possible uses of the "chord" (which is apparently what the patent tried to do). Unfortunately, everyone currently commonly plays "records" using a "diamond stylus" because that's the easy way to do it, so it apparently reads on their patent. However, that in itself might just make it obvious enough to invalidate their patent too, but easy and common does not necessarily make it "obvious" from a patent protection point of view (in fact some of the most valuable patents often illustrate how easy it is to do something new with an existing technique).
Also this inference I made doesn't address the issue of patentability of any specific methods to identify the "chord" in the "song" after you have read the "record" (which apparently is done with yet another common method and process which forms part of the diagnostics test that they tried to claim patent for). Maybe that part is "obvious" (in the patent sense) or easy to circumvent, but maybe not.
The difference between mRNA and cDNA is splitting hairs.
I don't buy that arguement. Let's say you have a phonograph (vinyl record), with a song. You could patent a phonograph player with a diamond stylus that transcribed that phonograph back to an audible sound, because that isn't only way to do it, you could also have a different instrument (say a laser-pickup), that transcribed that phonograph back to an audible sound and that would be a different invention.
However, in this case they are trying to patent using a phonograph to see if there is a specific chord on that record. Just because, everyone uses a diamond stylus to transcribe the record today, doesn't mean that that process to identify a specific chord on a record using a diamond stylus is or isn't patentable. You need to look more at the details. It may be that it doesn't pass the "obvious to someone skilled in the arts" test, but it isn't just on the face of it unpatenable or a product of nature.
FWIW, Clarence Thomas has written nearly 500 Supreme Court opinions during his tenure. A quick glance at a few years' statistics shows that he's often in the middle of the pack when it comes to writing opinions (both majority and dissenting)...
I'd assume that you can, in fact, apply to patent anything;
In the US, alleged "perpetual-motion" machines get a special carveout. Since they want your application fee, accepting your patent application is merely a formality. However, the USPTO specifically requires a working model for machines claiming perpetual motion (and waives this requirement for all other types of patents).
The UK simply does not accept application for patents that claim processes contrary to well-established physical laws and specifically call out a "perpetual-motion" machine as an example of such a patent application that would be rejected.
the release of DVD caused a collective groan due to the market confusion it created over whether its 480p was "hi-def" and the delay in HDTV standard that had been in the works since the 80's.
I don't think anyone called 480p "hi-def" (it is technically EDTV). Also, although the Japanese had MUSE/Hi-Vision and the Europeans had HD-MAC back in the 80's, they were both mostly analog HD broadcast systems that never really had a robust consumer media component (I doubt there were more than a hand-full of MUSE encoded HD laserdiscs titles...)
The MPEG standards track (that eventually became the digital HDTV standards) was "in-the-works" in the mid 90's (not the 80's). The MPEG-2 work originally targeted SD and was rushed by Hughes (for satellite tv) and the DVD folks to completion in 1996. Nobody was delaying anything in the standardization meetings as Hughes was clamoring to have the systems layered nailed down before they launched their direct broadcast satellites and the DVD folks wanted to launch products as soon as they could. For example, all the video "scalability" cruft that nobody uses in MPEG-2 were simply a concession to a few hold-outs to get the standard approved ASAP.
There was for a short time, a "MPEG-3" standard proposed targeting for HD after the MPEG-2 work was done, but none of the proposals were significantly better than MPEG-2 coding at HD resolution, so ***rather than delay*** digital HDTV rollout to develop something better, the MPEG-3 standardization effort was simply cancelled and the first digital HD standards were MPEG-2 based (both terrestrial and satellite).
Of course, eventually, the MPEG-4-AVC (aka H.264) was eventually developed (leveraging many of the tricks used by the video conferencing standards 'churn' creating an very complicated standard) and became the current defacto standard for HDTV (except for US terrestrial broadcast which is still MPEG-2 from the 90's)...
Actually, I think this C. S. Lewis quote (I think it was from God in the Dock) was an observation concerning the tyranny of Organized Religion, not Government. FWIW, C.S. Lewis also wrote the Chronicals of Narnia...
The full quote of the origin of your sig... It seems to have a different tone when you read the full context...
Western civilization, it seems to me, stands by two great heritages. One is the scientific spirit of adventure – the adventure into the unknown, an unknown which must be recognized as being unknown in order to be explored; the demand that the unanswerable mysteries of the universe remain unanswered; the attitude that all is uncertain; to summarize it – the humility of the intellect. The other great heritage is Christian ethics – the basis of action on love, the brotherhood of all men, the value of the individual – the humility of the spirit.
These two heritages are logically, thoroughly consistent. But logic is not all; one needs one's heart to follow an idea. If people are going back to religion, what are they going back to? Is the modern church a place to give comfort to a man who doubts Godmore, one who disbelieves in God? Is the modern church a place to give comfort and encouragement to the value of such doubts? So far, have we not drawn strength and comfort to maintain the one or the other of these consistent heritages in a way which attacks the values of the other? Is this unavoidable? How can we draw inspiration to support these two pillars of western civilization so that they may stand together in full vigor, mutually unafraid? Is this not the central problem of our time?
Rep. Peter King should be impeached and prosecuted...
Since it appears that every member of congress and the president of the United states knew about this spying program with briefs from the intelligence agencies annual authorization and approved it, what say you about them? What makes Rep. King so special? The mere fact that he is one of the voices calling for extradition? his name? or his party affiliation?, or...
Unless I'm mistaken, people are impeached and prosecuted for their ***crimes*** yet aren't people free to express the views that they want w/o being threatened with prosecution?
Or is this just some political rant you are going on about?
his numbers DO show substantial evidence that people just below passing are being bumped up to passing grades. although again it's hard to know for sure without knowing how the exam is weighted.
Testing is just like any other form of measurement. There are inherent uncertainties in every measurement scheme so you need to account for them.
I don't think many folks understand the CBSE marking scheme (I sure don't), but as I understand the basics, on some test sections (like math) there are a certain number of "1" point questions, a certain number of "4" point questions and a certain number of "6" point questions. People that score near the top of the range might miss a random smattering of "1" point questions, but for the "6" point questions, you apparently have a "choice" of answering a few different questions (presumably you would pick the one that you have the most confidence in) so you probably get them or not. The disparate points/question and the fact that you get to pick some questions might be able to explain the gaps in certain scores (to get a lower score, you likely need to miss some "6" point questions providing more quantization than missing a "1" point question). It seems to me quite likely that certain scores are highly unlikely or even unatainable.
OR, perhaps the during test reporting, the powers that be decide to give everyone the benefit of the doubt by rounding them up so that nobody misses an arbitrary cut-off by just 1 or 2 points... In the USA, you might even call this type of measure a defensive manuver (to avoid the inevitable numerous lawsuits from angry parents)...
Hard to say w/o knowing more details about the the specifics (for those interested you can find out yourself about the strange scoring system here on the CBSE website http://cbse.gov.in/welcome.htm)
As far as I can tell, they are mostly just doing a twist on something that was known a long time ago: quadrature modulation.
The way color TV transmission worked in the past (not anymore, it's all digital now, but I digress) was that they crammed 3 signals in the space original meant for black-and-white TV by basically converting RGB into Y (an approximation of the Black and White signal), and two color difference signals. These color difference signals were modulated to a high alternating frequency pattern (so that old B & W sets wouldn't see them very much) and then put into quadrature with each other (each signal getting about 1/2 the spatial frequency bandwidth, and essentially interleaving them in time). In some sense in quadrature modulation, you are hiding one signal in the "nulls" you create in the other signal.
In this so-called "cloak" technique, the modulation is more complex and instead of trying to transmit two equal bandwidth signals together, they are exploiting the fact that their is no reason that the split has to be equal...
The below example is overly simplified single-split case, but illustrates what is going on...
Original: Signal ~ sin(wt+kx) Phase Modulated signal with simple small split phase shift "p": Psignal ~ 0.5*sin(wt+kx+p)+0.5*sin(wt+kx-p) And using the magic of trigonometry... Psignal ~ sin(wt+kx)*cos(p)
If the transmitter controls the phase just right, the "cosine" modulates the original signal and creates periods of time where the amplitude is really low (not really zero except at a point), yet back to their nominal amplitude at the receiver. Since the transmitter know when these "nulls" will be, it can put in short bursts of another covert signals that looks nominally like the original signal (same base frequency), but won't really be visible at the receiver (presumably the transmitter would pick the phase parameters of this covert signal so that they were "null" at the receiver).
In practice, a single 50-50 split with complementary phase shift isn't really that great, you have to more harmonics approximate more interesting signal envelopes. Think about making a square wave out of harmonics and you can see how you might make the apparent "null" times much longer.
Thus to the outside observer it looks mostly like the original signal (same nominal frequency for symbols being transmitted since the phase shifts are small, it would just look like jitter), but the transmitter was able to finesse the transmission so that it could transmit relatively normally so that the receiver would still pick out the signal. During the "null" times, the transmitter could transmit a covert signal which isn't picked up by the normal receiver but looks like a plausible innocuous signal, so a simple cursory observation of the channel looks as if only generic transmission is going on.
We don't have to call this stuff using descriptions like temporal cloaks and erasing information from history. Except perhaps analog color tv transmission (may it RIP)
Slashdot Mirror
Everytime an electron passes from the metal interconnect to silicon in a semiconductor a quantum process is occuring. The electron has to pass a thin but but carrier empty region by quantum tunnelling because the metal either fills or empties the region of the interface. So the electron has to do a "quantum jump" so to speak. So basically every semiconductor is quantum to a degree and in an instrinic way.
Although everything has a quantum component when it is small (because quantum=physics and everything has to follow the laws of physics), this "tunnelling" aspect isn't really important part of the function of the IGFET as it is currently used.
Sure, with a metal/semi-conductor interface, there is a "depletion-region" which creates a potential barrier that needs to be overcome by electrons. As I understand it, the potential provided by the power-rails to switch the device are more than enough to overcome this potential barrier so this pretty much looks like an resistive (ohmic) contact and the tunnelling isn't an intrinsic part of the operation. This "depletion-region" is mostly interesting as a function of reduced switching speed and limitation of the saturation current through the channel causing more leakage in static operation (the "bad" stuff).
If we didn't provide enough potential by the power-rails to cross this potential barrier of the depletion region formed by a metal-semiconductor junction, then any charge that wanted to cross it would have to tunnel and that would be an intrinsic part of the operation of the device. The tunnelling current would be very small relative to the larger currents provided by the power-rails that are in common use today and would result in really slow transistors.
For the record - in flash memory what people refer to as 'tunnelling' might better be referred to as "electrical breakdown of a dielectric" ... People can call it tunnelling if they want to - but ask me this - if it is tunnelling and not electric breakdown (in the old fashioned classical sense) why are write cycles limited?? I know which of those two phenonoma damages materials in the long run - and it isn;t tunnelling..
In actuality, physics is always involved, so since a flash memory is an actual device, rather than a theoretical device, both processs are happening , but my understanding is that di-electric breakdown isn't currently the predominant process.
The difference between di-electric breakdown and tunnelling is that di-electric breakdown creates semi-permanent electrically conductive paths through the insulator where tunnelling does not, but statistically leaves some charge trapped in the insulator. The primary limitation of cells on current flash processes are oxide degradation due to the accumulation of **trapped charge** reducing the F-N tunnelling efficiency and also impairing the action of the control gate. In contrast di-electric breakdown will over time increase the amount of **charge leakage** through the insulator and will eventually make it difficult for the cell to retain information, but on current proceseses, that effect is smaller than the charge trapping issue.
FWIW, There has been some effort to try to develop a way re-anneal the oxide to reduce/eliminate the trapped charge issue (e.g., by locally heating it), so eventually that make the di-electric breakdown process the limiting factor, but that is still a bit researchy...
Is it really necessary to have the same number of qubit as the problem, tho?
Unfortunately, I think it's worse than that.
The "quantum" part of Shor's algorithm factoring N involves a period finding operation that requires an input and output of k-qubits where k is approximately 2logN+1. A simplistic implementation to factor a 2048-bit number would be minimally 2x2048+1 input and the same number of output so about 8194 qubits (I don't think you can share the input and output for the quantum fourier transform computation step). That also presupposes that you can change the circuit connecting these qubits into N configurations check each. We've got a long way to go before we are quantum factoring...
Transistors directly use quantum effects to work, yet we don't call desktop computers "quantum computers".
The transistors in the CPU in your desktop computer are IGFETs (insulated gate field effect transistors). The principle of operation of this device is that moving charge on the gate can enhance or deplete the number of mobile electrons in the source to drain channel under the gate and cause it to turn on or off using an electric field effect which is not considered a quantum effect.
To be fair, at the scales that modern transistors operate, there are some interesting quantum effects. Most are considered as "bad" (causing problems with the "classical" operation of the transistor by tunneling charge or changing thresholds), but there are a few things like strained silicon that are used to improve performance (which used to create quantum containment and effective mass modifications to make small geometry operation more feasible), but these quantum effects aren't intrinsic to the operation of a generic IGFET (just a FET that's really small).
There are of course stuff in your desktop computer that intrinsically rely on quantum effects to work. For example, the flash memory (uses tunneling to move charge in and out of an isolated control gate). However, there are many other things that are similar to the transistor's use of QM effects like the optical drive (solid state laser uses bandgaps to get a certain frequency) and the disc drive (uses the GMR effect which is related to QM electron spin transport), but that's really just to make stuff work when it is really small, not intrinsic to the operation.
In the end, it's all physics and computers use physics and when you make things really small the quantum nature of physics must be accounted for, but it can be taken advantage of too. As for calling a quantum adiabatic computer a "quantum computer" I agree that would be a no. It technically relies on tunneling, so it's sort of like a flash memory in that respect (it's basic theory of operation requires a non-classical QM effect which is different than a transistor).
As to whether D-Wave actually does or doesn't implement a QM adiabatic algorithm, or perhaps just uses QM tunneling to improve a more classical annealing implementation speed and result, and if that actually makes any practical difference, is another question.
guarantee equivalent function
Isn't that undecidable (in general)?
It is decidable, but some cases are exponentially hard to decide (and the Logic Equivalence Checking or LEC tools will barf).
Quick background. The task of converting a logical representation of a chip function to a physical representation is a very time consuming process, so often if a bug is found or a timing problem is found, you don't want to restart the process, but instead you probaly to make a small local change (equivalent to patching a binary to fix bug rather than recompiling). But when you create that patch, how do you know that it does what you want?
That's why they make LEC tools (like Formality). If you made a timing/retiming fix, you can be assured it doesn't change the functionality, if you made a small bug fix, you can fix the source code run your tests and know that the results apply to the patched version as well.
If you tried to run LEC tools on a whole chip, it would generally barf. You generally have to run it on small blocks of the chip and build up your equivalence check for the whole thing hierarchically.
LEC tools run in a reasonable computing resource configuration because big chunks of the design are exactly the same and the primitive binary operations in IC design have simple to define properties that have easy to describe using efficient structures like ROBDDs. If you tried to take this approach on typical software executable, you would likely quickly find that either there is no efficient data structure to evaluate equivalence, or that the primitives that are reasonably efficient don't have simple to define properties (e.g, FP math is not associative, deltas in non-live/don't care parameters/registers/stack-values).
Some complementary work done at UT-austin
Instead of a membrane matching the impedence of a "meta-material" made by punching regularly spaces in a wall (kind of like a meta-material drum), the UT-austin work describe holes made with a "meta-material" approach. Basically a hole with some transverse tubes cut a regular intervals to create resonances that change the effective impedance parameters allowing pretty much lossless transmission through the hole (kind of like a meta-material horn).
Although MSFT claimed to lock down WinRT to force developers to target Metro so there would be lots of tablet friendly apps instead of win32 ports, my theories as to why MSFT really decided to have a locked down WinRT...
1. They are mostly using WinRT as a lever against Intel to get them to reduce the margins on x86 chips so that they can compete against android in the low-end tablet space w/ x86 chips. If this strategy is successful and intel capitulates, they didn't want too many consumer WinRT ARM win32 binaries floating in the wild to support as they drop support for ARM.
2. They wanted to sell unlocked versions to enterprises at a higher price.
3. Available ARM SOCs are 32-bit and the GPUs don't yet have universal support for DX10 (the minimum required for win8) and they don't want developers to go back a generation to the lowest common denominator just to pickup WinRT compatibility as that would undermine the upgrade cycle component of their business.
4. They didn't want to support malware/anti-virus on ARM (maybe because of $$$ supporting too many platforms or maybe slow performance on ARM).
All these reasons could change in the future, but they were probably important during the original launch (and thus they flipped the flag to lock it down).
As a non-physicist, my understanding of the Higgs mechanism is pretty weak, but...
The way I understand it the generic idea of the Higgs mechanism isn't simply restricted to be a "mass-generating" mechanism, although the most interesting Higgs mechanism that are searched for are the ones that can suggest electro-weak symmetry breaking which gives non-zero rest masses to W and Z bosons. The reason why most folks are searching for something that can describe this is that W and Z boson have the largest masses (~85x a proton) whereas a simplistic assumption of symmetry in the electric and weak fields would imply that these particles have zero-mass.
The generic Higgs mechanims pre-supposes a field (which exists everywhere there is the effect). Simplistic assumptions of convervation properties of the field manifest themselves as certain symmetries (which imply other symmetries and can be put into a mathematical framework similar to gauge groups, but that's not too important). The question becomes since the classical equations describe a mass-like scalar term that seems to be independent of the gradients and couples to these fields, how can we put a mass-like term into a framework with all these symmetries, yet be have it be non-zero?
The basic idea is that the field must have some sort of symmetry-breaking. At some high-energy (or temperature or potential), the expected value of the mass-like term averages out to zero, but as you go towards low-energy (or temperature, or potential), the expected value becomes non-zero yielding a mass-like term. As it turns out, if the potential of the field is shaped like a W or a sombrero, it can have this property. At high potential (when you can't see the "hat" part), the expection is symmetric around zero and the field has the required symmetry. As the potential goes down (including all the way to zero), the low-energy expectation value falls away from zero (at a consistent radius away from the center because of the "hat"). This is apparently called spontaneous symmetry breaking.
Why would the field potential have this shape? Who knows? But if it does, it can simultaeously satisfy the symmetries and still have a gradient/direction independent expected value term (which would act just like a scalar constant just like mass in all the classical physics formulas).
So what everyone is calling the Higgs field (and higgs particle) are mostly a specific interaction that describes how the W and Z boson can appear to have a non-zero mass-like term with electro-weak symmetry breaking. It is my understanding that it is currently just assumed that all other stuff that has non-zero mass would be similar, but it doesn't really explain what people think of as mass per-se (which has a mysterious gravitational equivalence), it just gives a explanation for the observations that are likely consistent with mass in terms of energy of the various fields (other than gravity).
VP9 will be completely open. Just remember that creating video codecs is very complex process on its own, so adding things like encryption schemes will likely require a bunch of professional engineers.
I'm not sure what to take away from that statement about "professional engineers".
It seem like you implying that since VP9 didn't want/need "the community" (of presuably unprofessional folk) in its development that somehow the current developers of VP9 don't feel that "the community" can develop an encryption schemes (being the unprofessional folk we are)?
I gather that the Cathederal mechanism of development might be deemed necessary (by google) to avoid IP contamination of VP9, but as someone that does stuff in this area (video compression and encryption) professionally, what you seem to be implying is a bit condecending to "the community" of open source developers (many of whom are professional engineers in our day-jobs)...
In fact, I might argue that encryption schemes are best done in the community (e.g., like the AES and the SHA-3 process) because an open competitive environment is the best way to assure the actual difficulty of cirvumenting the scheme is known (rather than assuming that some experts have it figured out).
http://www.sfexaminer.com/sanfrancisco/fair-is-taking-digital-leap/Content?oid=2442281
http://sanfrancisco.cbslocal.com/2013/06/13/hi-tech-exhibits-join-farm-animals-carnival-games-at-san-mateo-county-fair/
Among the additions this year are a 3-D printer, a Frisbee-throwing robot made by students at Aragon High School, and a "reverse-engineering" exhibit where kids can take apart VCRs and computers to see how they work. Colaluca also has organized competitions in coding and app-making, and he deputized employees of local computer companies to judge them.
Because there happens to already be a cheap way of amplifying a small sample of DNA for identification (PCR).
Most other easy to manufacture serializable microscopic substances mostly suffer from dillution/detection problems.
The technique is to use junk DNA encoded with a serial number. DNA are the is the microscopic grains and PCR is the way to quickly do the detection if a specific serial number is present (although PCR isn't yet as simple as a swab).
Presumably you could spend years doing revolutionary nobel prize winning research and replace DNA with another chemical that had an even cheaper way of detection for this niche application, but someone who worked for Applied DNA Sciences might instead think about just using DNA and an existing nobel prize winning PCR test and get something to market faster.... Just say'n... ;^)
the plane airbus did not want to build at the time, as they just blew up their budget on the A380 delay
FTFY...
Basically, Airbus's parent company (EADS) simply didn't want to invest that much of their own money on a new development and wanted to pressure the european governments into some sort of financing trick***. That didn't happen, so EADS reluctantly spent their own money on A350XWB development (and basically they have been mostly cash-flow negative since then which really puts a crimp on the value of the executive's stock options).
*** it's a bit complicated, but because of the WTO dispute with Boeing, the government can't really just give or loan the money to EADS for new development w/o triggering potentially expensive trade retaliation, but governments can loan money for something called "launch-aid" (temporary funding *after* development to finance inventory and supply chain buildup). It's always a bit suspicious when "launch-aid" loans happen before the development even starts (which seems to frequently happen with Airbus as they use the uncertaintly of location of jobs as enticements)...
So basically, they reinvented the train...
Maybe the consumer version will be like this...
record=chromosome
song=the DNA in some specific person's chromosome
chord=mutated BRCA gene
diamond stylus=the cDNA technique to read DNA
laser pickup=some new way to read DNA
AFAIK the decision was that the "chord" is not patentable, because it's part of the naturally occurring "song".
However, since the current method to find if the "chord" is present in the "song" uses a "diamond stylus" pickup to read the "record" and is described in a patent, it might be patentable (they didn't address this in the ruling the issue of obviousness) since it uses a method to read the "song" which isn't a natural process. SCOTUS simply upheld the patent (it still can be re-examined).
The inference I made is that if someone else comes up with another way to detect the "chord" in the "song" that doesn't use a "diamond stylus" (say a "laser pickup" mechanism, or taking a picture of the groves on the record and having a computer recreate the audio), then the current patent is totally circumvented because SCOTUS says that it is not possible to patent nearly all possible uses of the "chord" (which is apparently what the patent tried to do). Unfortunately, everyone currently commonly plays "records" using a "diamond stylus" because that's the easy way to do it, so it apparently reads on their patent. However, that in itself might just make it obvious enough to invalidate their patent too, but easy and common does not necessarily make it "obvious" from a patent protection point of view (in fact some of the most valuable patents often illustrate how easy it is to do something new with an existing technique).
Also this inference I made doesn't address the issue of patentability of any specific methods to identify the "chord" in the "song" after you have read the "record" (which apparently is done with yet another common method and process which forms part of the diagnostics test that they tried to claim patent for). Maybe that part is "obvious" (in the patent sense) or easy to circumvent, but maybe not.
The difference between mRNA and cDNA is splitting hairs.
I don't buy that arguement. Let's say you have a phonograph (vinyl record), with a song. You could patent a phonograph player with a diamond stylus that transcribed that phonograph back to an audible sound, because that isn't only way to do it, you could also have a different instrument (say a laser-pickup), that transcribed that phonograph back to an audible sound and that would be a different invention.
However, in this case they are trying to patent using a phonograph to see if there is a specific chord on that record. Just because, everyone uses a diamond stylus to transcribe the record today, doesn't mean that that process to identify a specific chord on a record using a diamond stylus is or isn't patentable. You need to look more at the details. It may be that it doesn't pass the "obvious to someone skilled in the arts" test, but it isn't just on the face of it unpatenable or a product of nature.
FWIW, Clarence Thomas has written nearly 500 Supreme Court opinions during his tenure.
A quick glance at a few years' statistics shows that he's often in the middle of the pack when it comes to writing opinions (both majority and dissenting)...
http://en.wikipedia.org/wiki/2012_term_opinions_of_the_Supreme_Court_of_the_United_States
I'd assume that you can, in fact, apply to patent anything;
In the US, alleged "perpetual-motion" machines get a special carveout. Since they want your application fee, accepting your patent application is merely a formality. However, the USPTO specifically requires a working model for machines claiming perpetual motion (and waives this requirement for all other types of patents).
The UK simply does not accept application for patents that claim processes contrary to well-established physical laws and specifically call out a "perpetual-motion" machine as an example of such a patent application that would be rejected.
the release of DVD caused a collective groan due to the market confusion it created over whether its 480p was "hi-def" and the delay in HDTV standard that had been in the works since the 80's.
I don't think anyone called 480p "hi-def" (it is technically EDTV). Also, although the Japanese had MUSE/Hi-Vision and the Europeans had HD-MAC back in the 80's, they were both mostly analog HD broadcast systems that never really had a robust consumer media component (I doubt there were more than a hand-full of MUSE encoded HD laserdiscs titles...)
The MPEG standards track (that eventually became the digital HDTV standards) was "in-the-works" in the mid 90's (not the 80's). The MPEG-2 work originally targeted SD and was rushed by Hughes (for satellite tv) and the DVD folks to completion in 1996. Nobody was delaying anything in the standardization meetings as Hughes was clamoring to have the systems layered nailed down before they launched their direct broadcast satellites and the DVD folks wanted to launch products as soon as they could. For example, all the video "scalability" cruft that nobody uses in MPEG-2 were simply a concession to a few hold-outs to get the standard approved ASAP.
There was for a short time, a "MPEG-3" standard proposed targeting for HD after the MPEG-2 work was done, but none of the proposals were significantly better than MPEG-2 coding at HD resolution, so ***rather than delay*** digital HDTV rollout to develop something better, the MPEG-3 standardization effort was simply cancelled and the first digital HD standards were MPEG-2 based (both terrestrial and satellite).
Of course, eventually, the MPEG-4-AVC (aka H.264) was eventually developed (leveraging many of the tricks used by the video conferencing standards 'churn' creating an very complicated standard) and became the current defacto standard for HDTV (except for US terrestrial broadcast which is still MPEG-2 from the 90's)...
Actually, I think this C. S. Lewis quote (I think it was from God in the Dock) was an observation concerning the tyranny of Organized Religion, not Government.
FWIW, C.S. Lewis also wrote the Chronicals of Narnia...
The full quote of the origin of your sig... It seems to have a different tone when you read the full context...
Western civilization, it seems to me, stands by two great heritages. One is the scientific spirit of adventure – the adventure into the unknown, an unknown which must be recognized as being unknown in order to be explored; the demand that the unanswerable mysteries of the universe remain unanswered; the attitude that all is uncertain; to summarize it – the humility of the intellect. The other great heritage is Christian ethics – the basis of action on love, the brotherhood of all men, the value of the individual – the humility of the spirit.
These two heritages are logically, thoroughly consistent. But logic is not all; one needs one's heart to follow an idea. If people are going back to religion, what are they going back to? Is the modern church a place to give comfort to a man who doubts Godmore, one who disbelieves in God? Is the modern church a place to give comfort and encouragement to the value of such doubts? So far, have we not drawn strength and comfort to maintain the one or the other of these consistent heritages in a way which attacks the values of the other? Is this unavoidable? How can we draw inspiration to support these two pillars of western civilization so that they may stand together in full vigor, mutually unafraid? Is this not the central problem of our time?
Violating your oath of office is a high crime and/or treason...
Does the buck stop at the top (the president who knew about it could have vetoed it?)
Rep. Peter King should be impeached and prosecuted...
Since it appears that every member of congress and the president of the United states knew about this spying program with briefs from the intelligence agencies annual authorization and approved it, what say you about them? What makes Rep. King so special? The mere fact that he is one of the voices calling for extradition? his name? or his party affiliation?, or ...
Unless I'm mistaken, people are impeached and prosecuted for their ***crimes*** yet aren't people free to express the views that they want w/o being threatened with prosecution?
Or is this just some political rant you are going on about?
his numbers DO show substantial evidence that people just below passing are being bumped up to passing grades. although again it's hard to know for sure without knowing how the exam is weighted.
Testing is just like any other form of measurement. There are inherent uncertainties in every measurement scheme so you need to account for them.
I don't think many folks understand the CBSE marking scheme (I sure don't), but as I understand the basics, on some test sections (like math) there are a certain number of "1" point questions, a certain number of "4" point questions and a certain number of "6" point questions. People that score near the top of the range might miss a random smattering of "1" point questions, but for the "6" point questions, you apparently have a "choice" of answering a few different questions (presumably you would pick the one that you have the most confidence in) so you probably get them or not. The disparate points/question and the fact that you get to pick some questions might be able to explain the gaps in certain scores (to get a lower score, you likely need to miss some "6" point questions providing more quantization than missing a "1" point question). It seems to me quite likely that certain scores are highly unlikely or even unatainable.
OR, perhaps the during test reporting, the powers that be decide to give everyone the benefit of the doubt by rounding them up so that nobody misses an arbitrary cut-off by just 1 or 2 points... In the USA, you might even call this type of measure a defensive manuver (to avoid the inevitable numerous lawsuits from angry parents)...
Hard to say w/o knowing more details about the the specifics (for those interested you can find out yourself about the strange scoring system here on the CBSE website http://cbse.gov.in/welcome.htm)
As far as I can tell, they are mostly just doing a twist on something that was known a long time ago: quadrature modulation.
The way color TV transmission worked in the past (not anymore, it's all digital now, but I digress) was that they crammed 3 signals in the space original meant for black-and-white TV by basically converting RGB into Y (an approximation of the Black and White signal), and two color difference signals. These color difference signals were modulated to a high alternating frequency pattern (so that old B & W sets wouldn't see them very much) and then put into quadrature with each other (each signal getting about 1/2 the spatial frequency bandwidth, and essentially interleaving them in time). In some sense in quadrature modulation, you are hiding one signal in the "nulls" you create in the other signal.
In this so-called "cloak" technique, the modulation is more complex and instead of trying to transmit two equal bandwidth signals together, they are exploiting the fact that their is no reason that the split has to be equal...
The below example is overly simplified single-split case, but illustrates what is going on...
Original: Signal ~ sin(wt+kx) ... Psignal ~ sin(wt+kx)*cos(p)
Phase Modulated signal with simple small split phase shift "p": Psignal ~ 0.5*sin(wt+kx+p)+0.5*sin(wt+kx-p)
And using the magic of trigonometry
If the transmitter controls the phase just right, the "cosine" modulates the original signal and creates periods of time where the amplitude is really low (not really zero except at a point), yet back to their nominal amplitude at the receiver. Since the transmitter know when these "nulls" will be, it can put in short bursts of another covert signals that looks nominally like the original signal (same base frequency), but won't really be visible at the receiver (presumably the transmitter would pick the phase parameters of this covert signal so that they were "null" at the receiver).
In practice, a single 50-50 split with complementary phase shift isn't really that great, you have to more harmonics approximate more interesting signal envelopes. Think about making a square wave out of harmonics and you can see how you might make the apparent "null" times much longer.
Thus to the outside observer it looks mostly like the original signal (same nominal frequency for symbols being transmitted since the phase shifts are small, it would just look like jitter), but the transmitter was able to finesse the transmission so that it could transmit relatively normally so that the receiver would still pick out the signal. During the "null" times, the transmitter could transmit a covert signal which isn't picked up by the normal receiver but looks like a plausible innocuous signal, so a simple cursory observation of the channel looks as if only generic transmission is going on.
We don't have to call this stuff using descriptions like temporal cloaks and erasing information from history. Except perhaps analog color tv transmission (may it RIP)
One guy said, "I figure my chances of winning are 50-50. Either I win or I don't."
You might laugh, but this is the starting point of Laplace's Rule of Succession (an important rule in baysian statistical estimation)... ;^)