Surely energy policies are about creating a feel-good aspect to the brand. Plus if you learn something along the way by trying perhaps you can commercialize it and it takes you off on another wild ride, like the iPhone did.
Directors and officers of a corporation have a fiduciary duty to the stockholders to run the company in their interest.
This USUALLY means trying to maximize return on investment. But the sotckholders may want other things, in addition to or in place of, financial gain. When this is the case, the duty requires them to set their own target appropriately.
This is not uncommon: Think "green energy company" or "church" for two examples. The Bell Telephone company, started by Alexander G. out of his research into hearing aids, has always done work on assisting the hearing impaired. Hershey's, at the direction of its founder, is owned by a trust and 30% of its profits go to support a school for orphans.
One typical strategy is to "satisfice", rather than maximize, financial gain, while pursuing other interests. This produces a sound financial base for pursuing those interests. (i.e. Hershey's, churches, "green companies"...) Another is to do things that are win-win with respect to the business (i.e. Bell Telephone, doing things like designing phones to work well with hearing aids, make ringing sounds that are auddible to the partially deaf and light-flashing ringer devices, and otherwise making the phone system accessable to hearing impaired.)
As you point out, these approaches may also lead to financial benefits that typical businesses and business-school graduate executives miss in their pursuit of the short-term bottom line. Good will, new inventions, synergies, etc.
Another example: Hershey's, not constrained or incentivized by short-term bottom-line, doesn't use typical industrial-food ingredients such as corn syrup, or follow other food-processing fads. It sticks with basic, high quality, time-proven, ingredients and recipies. This produces a consistent product (which also forms the base for consumer recipies) and a loyal customer base. (No "New Coke" debacle or gradual deterioration of product quality over decades with this company.)
When I was working in retail about 5 years ago competitors of ours did the same. Our store name, their phone number.
That reminds me of why dial phones were invented.
Early telephone exchanges used an operator to connect all calls. You picked up the phone and this lit a lamp and sounded a buzzer at an operator's console in the central office. The operator pulgged a cable into a jac and talked to you, found out who you wanted to talk to, and plugged another cable into the other customer's jack (or a trunk to another operator) to hook you up. Similarly when you hung up, or (if the call needed some other modification and you "flashed" by flicking the hook switch).
Some businesses bribed unscrupulous operators to redirect their competitor's calls to them, stealiing some of their buiness (especially in high customer turnover businesses, where a large fraction of the calls were initial contacts.) There was much flap over this, of course.
One such customer - an undertaker - decided to attack this problem at its root. He also happened to be what we'd now call a hacker (in the "exceptionally competent technologist" sense). He developed the earliest version of a dial telephone system, and got one of the telephone companies serving his area to install it. Electromechanical stepper switches were not susceptable to bribery, problem solved.
Of course electromechanical stepper switches are also cheaper than even low-wage people. So dial systems caught on very quickly. You still needed operators for non-simple stuff, but a company handling the bulk of the calls mechanically needed far less of them, and when such service was available businesses switched over en masse.
I find myself wondering if it can be combined with MIMO. That would be very cool.
It IS MIMO: the special case where:
- The base station antennas are widely separated.
- The data is mapped so each remote antenna gets a particular one-spectrum-channel-worth subset of the data stream (rather than several antennas getting several spectru-channels worth, but in the form of differently phased-and-weighted sums of several carriers with mixes of the data). This allows the remobe devices to work with a single antenna that can move around independently of the others.
There's no reason the signal can't be mapped so that a device with two or more sufficiently separated antennas can receive roughly as many spectrm-channels worth of bandwidth as it has antennas.
Might not be practical on a handset (at least not at frequencies below 3GHz), because there is not enough space to put adequate separation between antennas, but it could work well with tablets and other physically larger devices.
You called it. The separation doesn't need to be all that large (if the device is positioned near enough to the base stations that it "sees" adeqiate separation of the base antennas). But it does need to be at least in the ballpark of a quarter wavelength or more, even in the best of cases.
Spreading the component antennas of the MIMO base station out to different cell towers expands the area where MIMO tricks can be fully utilized in proportion - at the cost of requiring precise synchronization of local oscillators among the various antenna sites (and precise compensation for relative sway of the cell towers). But it doesn't require any changes at the remote end of the link - those antennas need the same separation for a given frequency and given perceived angular separation of the base antennas, regardless of the distance to the base antennas. (Spreading them further just means the remote can resolve smaller apparent angles, and thus work in more-than-spectrum mode further from the set of base stations.)
Sounds like, in the process of creating the virtual-reality hand model, they've also identified, extracted, and processed EXACTLY the signals necessary to operate a prosthetic.
This gives us the expectation that with the cybernetic prosthetic in place the phantom limb pain may not be a problem, as well.
(Of course that's presuming the summary is correct and it is confirmed.)
Steerable Null (alias DIDO or pCell) (the latter being steerable null with widely separated antennas) effectively multiplies the avaliable bandwidth by the number of base station antennas (by giving each remote a signal containig the full band's bandwidth directed to it, while the similar, simultaneous, signals to the other remotes cancel out).
Some posters were wondering what would be the driver for adopting it. This is it: There's no more spectrum being made - but this is a way to use it simultaneously multiple times without interference between the reuses.
Tesla vehicles are not green. The fact that it costs close to $100k should indicate that it is a very resource intensive product.
Actually it indicates that the early adopters are paying for building a car company and designing the car, not just the car itself, This is a proven model for new tech.
That "prissy pedal" makes the Model S go from 0 to 60 in 4 seconds and do a quarter mile in 12.5s. That's faster than a Porsche 911.
And that's much of why Tesla beats the competition.
Electrtic cars inherently COULD accelerate as much as possible given the coefficient of friction of tires on pavement. Electric motors generally have max torque at stall. All you need is a big enough motor and power supply. (What matters is being able to apply the necesary power during accelleration, which is a whole separate issue from cruising mileage.)
Unfortunately, other electric car manufacturers have been thinking "eco freeks in their underpowered compact and mini cars" and building underpowered electric powertrains. Martin Eberhard and Marc Tarpenning, along with the engineering team they assembled, did not make that mistake. Instead they designed a vehicle with the horsepower to have high performance.
The computation for DIDO (- steerable null) is a matrix multiply. Two additions + 2 adds times the product of the number of base station antennas and the number of active remotes.
Sorry, typo: Two multiplies and two adds. Ammortized per channel it's only an extra (multiply and add) * 2 * number of antennas for each I + Q sample of the generated waveform.
I'm seeing no mention of latency here. Running expensive computations to reconstuct the signal is going to add a considerable amount latency, which more or less eliminates video-chat applications.
Nope. It's done in a DSP, just like the computations that form the modulation/demodulation in the first place. It's blazingly fast (it HAS to be because you do it for every sample of the signal.)
The computation for DIDO (- steerable null) is a matrix multiply. Two additions + 2 adds times the product of the number of base station antennas and the number of active remotes. This is quite small compared to the number of computations to make the signals: An (inverse for transmit) FFT for each channel.
And this is a computation which gets more complex the mode devices you have in an area too.
(I'm not used to the tuchpad on my new laptop and seem to have actidentally posted mid-edit.)
The cure for this is to disable the trackpad (Alt+F7 on many laptops) and use the arrow keys or a mouse. WFM.
Thanks, but alt-f7 doen't do it on mine (which is running ubuntu 12.04 LTS>. Instead it emulates a left-click-and-hold to grab the object under the cursor.
I've got a little script that lets me toggle the enable/disable state but hadn't hooked up the mouse and activated it just then, so the touchpad was live.
I've tried to find an option for havig the the touchpad automagically go dead when the mouse is live (as windows has), but haven't found it in Ubuntu 12.04's unity. If anybody knows how to set that please let me know.
As I read this, DIDO is exactly "steerable null" with the antennas spread out.
Of course the antennas are spread out VERY FAR APART, as in to multiple sites using a central computation of the I/Q signal and synchronizing separate local oscillators at the remote sites. This results in "bubbles around", rather than "beams at", those cellpphones that are in among the antennas.
Isn't that the study that got debunked because it turmed out the bulk of the people rating astrology as scientific had misread it as "astronomy"?
If so, it might say more about Democrats' literacy than their their belief in astrology.
It would also be what is expected, given that the consituency of the Democratic party is heavily weighted toward groups of people who have been the victims of poor public schools.
It sounds like a logical extension of phased-array technology. Or, sort of how they do radiation cancer treatment with dozens of weak beams converging on one spot.
The former. Phased array is coherent (phase between sources is controlled and signals can cancel). Reverse-tomography radiation treatment is incoherent (phase is uncontrolled and energy only adds - but you make it strong in one place and as weak as practical elsewhere, or especially weak at other particularly radiation-sensitive sites.)
(I'd love to see a holographic tomography system, using, say, coherent x-rays. gamma rays, or even tunneling charged particles. B-) The closest I've heard of is the muon beam, where the muons decay at a particular distance from the accellerator that makes them, making a "bright star" spot on the end of a "dim rod")
Precisely. The equivalent computation is done in the receive pipe, so the base station system "hears" from each bubble separately, as well as "speaking" separately to each.
In fact it has to be done this way, or you'd only get the bandwidth multiplication in the outbound direction and the inbound direction would be sharing the bandwdith. (Fortunately the transmit and receive pathways are exactly duals of each other.)
The only similarity between DIDO and MIMO, as far as I understand it, is that they both use multiple antennas to send and receive separate data streams simultaneously. But their signal processing schemes are very different.
Not really. See below.
In broad strokes: DIDO does the signal processing (matrix math) on the transmitter side while MIMO does it on the receiver side.
Nope. MIMO does it at BOTH ends, to multiply the bandwidth between the two ends of the path by up to the number of antennas at the end with the smaller antenna count. The subchannels are, or can be, actually received by all the receive end antennas and sorted out in the receiver.
DIDO is MIMO with:
- The computation done so each remote-end antenna gets exactly one subchannel of the data (rather than a weighted and phase-shifted sum of all subchannels).
- The antennas at both ends very widely separated.
Sorting the signals this way allows the "remote end" to consit of many, independent, single-antenna devices, each with an independent data pipe as broad as the assigned spectrum. The wide separation of the antennas at both ends of the link makes a very large coverage area practical. Motion of the remote end devices just corresponds to a variation in the position and spacing of a remote-end MIMO device's antenna, requiring update of the parameters of the computation.
As is MIMO (which is more general but includes phased array as a special case when the number of antennas at one end of the link is one.)
However, it has significant challenges with timing, since now motion of the antenna becomes a huge factor (more than 1/4 wavelength in position uncertainty shits out the effect of an individual element.
At the customer end this is not a problem, since it's the difference of the paths to the various base antennas that matters. An easier way to visualize it is to notice that the technique creates bubbles where essentially only the desired channel is received (and from which the transmitted signal is the only one of the subscribers received in the corresponding uplink channel after the DIDO processing). As you move away from the middle of the bubble the signals to the other subscribers begin to rise from the noise floor - but that's slow enough that the DIDO computation can be updated. (I suspect that for phones in vehicles the "DIDO data center" will need to estimate the speed and direction of the target (i.e. the way the phases of the signals are changing) and continuously update the computation, interpolating between actual measurements.
Changes to the relative position of the base antennas is much more significant:
This will be fine for antennas that are solidly connected to buildings in the lower bandwidths, but useless for 1800/1900 MHz on towers. Yes, they do move that much.
But they're massive and move slowly - far below an audio rate (in essentially two dimensions, i.e. a subsonic stereo signal). So this can be included in the computation.
You'll want to feed the measurements of the antenna motion back to the DIDO center, which would be very low bandwidth. Doing the computation at the antenna site would require broadening the pipe to/from it to be as wide as the sum of the max bandwidth to ALL the subscribers rather than the max bandwidth to one. You'll also want to estimate the motion a little bit ahead on the base-to-subscriber side, to tune out the measurement/transmission delay of the antenna position info going to the cener and the computed waveforms going to the antenna.
Ideally the phones would have a similar mechanism but current 4G LTE phones do not. they are omnidirectional and broadcast noise in all directions, even if the antenna system is at a specific location.
That doesn't matter. You just do the equivalent computation on the returned signal. You "listen" separately to the individual bubbles, just as you send separately to them.
So you only need to do it at one end - the one where coordinating and combining the signals is practical.
(I'm not used to the tuchpad on my new laptop and seem to have actidentally posted mid-edit. Reposting the full version.)
Even though it is technically compatible with 4G you still have to deploy millions of new antennas. He may have invented the greatest wireless technology ever, but it's dead on arrival due to cost.
Actually it may be cheaper than buying more spectrum and putting in more equipment at the cell sites, since it doen't involve buying more spectrum.
It DOES involve putting in more cells. But far fewer than you'd need to put in to subdivide the cells, in the normal cellular paradigm, to get the same amount of bandwidth reuse multiplication.
Also: You can bootstrap it by putting the new computation into just the existing cells, letting you handle more connections than with the old scheme. (After that it's add more cells in the customary maner, with more bang per buck.) Not only that, you only need to do it in areas where you're already running out of base station capacity and starting to suffer service level problems due to oversubscription/congetioin. If replacing/upgrading the equipment in existing cells gives you more additional connections per buck than the alternatives, there's no adoption cliff at all.
Even though it is technically compatible with 4G you still have to deploy millions of new antennas. He may have invented the greatest wireless technology ever, but it's dead on arrival due to cost.
Actually it may be cheaper than buying more spectrum and putting in more equipment at the cell sites, since it doen't involve buying more spectrum.
It DOES involve putting in more cells. But far fewer than you'd need to put in to subdivide the cells, in the normal cellular paradigm, to get the same amount of bandwidth reuse multiplication.
Also: You can start it by putting the new computation into just the existing cells and handle more connections than with the old scheme. (After that it's add more cells in the customary maner, with more bang per buck.) If replacing/upgrading the existing cells gives you more
Modern LEDs and modern fluoresent tubes have comparable efficiency.
In more detail: LEDs have the potential to be about as much more efficient than switcher-ballasted flurorescents as such fluorescents are more efficient than generic incandescents. Actual LED fixtures have been improving and right now are at the point where they're matching and starting to edge past fluorescents.
Give 'em a few more years and LEDs should be substantially ahead of fluorescents. But this year they're just about tied.
(This is why I haven't replaced my fluorescents with LEDs yet. I plan to do it in a few more years, when my current stock of spares, enough for about one more bulb change, is used up. I'm abouit to switch the yard lghting, though, because the motion detector / fluorescent fixture combination has been problematic and is now failing.)
"Crossing the Chasm" is about more revenues by making a tech product more mainstream. It has nothing to do with cutting investments.
My objection to "Crossing the Chasm" is about a different issue: Cutting the early hires out of their equity positions by terminating the vesting of their stock options and possibly high salaries, so the company growth rewards go to the founders and the high officials rather than to the talent in the trenches that actually turned the hairbrained scheme into a functioning enterprise.
In the process the company typically dumps them before it is really ready to succeed without them. What they're doing for the company, and what information is in their heads but not well documented, isn't sufficiently visible to the executives - especially the new team that is trying to force the transition.
This zinger is in the last couple paragraphs of one of the chapters near the end of the book. (Unfortunately I don't have my copy handy or I'd give you the page number and quote.)
I've watched this happen at least three times here in Silicon Valley.
- Exec enthuses about the book.
- Couple months later the company lays off the early hires.
- Product development grinds to a near-halt as problems arise and don't get solved. Shipments are missed, or go out with major quality issues. Customer support fails.
- Within about a year the company goes belly-up.
Now it's just a bunch of MBAs trying to massage their stock price.
You got that right.
Algorithm:
- Get hired for a big salary and a LOT of stock options.
- Make the company appear more profitable by cutting off investments in the future to reduce costs now.
- Declare victory and what a great guy you are.
- Cash in the stock options and move on to a bigger company where you can repeat the process for even more money and reputation points. PROFIT!
- Your successor inherits the house of cards and takes the blame when it collapses a few years later.
The Harvard Business School has a reputation for graduates who use this algorithm.
Interestingly, boards of directors keep falling for this. (You'd think they'd look at what happens to companies candidates had "turned around" in the several years AFTER they left when evaluating CEO, COO, and CFO candidates. But apparently they usually don't.)
= = = =
Similarly, if a high company official starts enthusing about the book "Crossing the Chasm" and you're an early hire, cash any vested stock options and get out, before you and the other early hires are laid off. (Interestingly, they usually fire them too soon, when they're still key to the company's success, and the company usually falls INTO the chasm rather than crossing it.)
In case you don't get it: It's obviously intended to mimic a fake anti-malware product that spams people with ads for itself.
Yes, there is a product by that name, which is called out as a "borderline scam" - though mainly with claims that it does little (removing key-only registry entries), may cause trouble, and buying it can result in a periodic charge to your credit card that is difficult to stop.
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Directors and officers of a corporation have a fiduciary duty to the stockholders to run the company in their interest.
This USUALLY means trying to maximize return on investment. But the sotckholders may want other things, in addition to or in place of, financial gain. When this is the case, the duty requires them to set their own target appropriately.
This is not uncommon: Think "green energy company" or "church" for two examples. The Bell Telephone company, started by Alexander G. out of his research into hearing aids, has always done work on assisting the hearing impaired. Hershey's, at the direction of its founder, is owned by a trust and 30% of its profits go to support a school for orphans.
One typical strategy is to "satisfice", rather than maximize, financial gain, while pursuing other interests. This produces a sound financial base for pursuing those interests. (i.e. Hershey's, churches, "green companies"...) Another is to do things that are win-win with respect to the business (i.e. Bell Telephone, doing things like designing phones to work well with hearing aids, make ringing sounds that are auddible to the partially deaf and light-flashing ringer devices, and otherwise making the phone system accessable to hearing impaired.)
As you point out, these approaches may also lead to financial benefits that typical businesses and business-school graduate executives miss in their pursuit of the short-term bottom line. Good will, new inventions, synergies, etc.
Another example: Hershey's, not constrained or incentivized by short-term bottom-line, doesn't use typical industrial-food ingredients such as corn syrup, or follow other food-processing fads. It sticks with basic, high quality, time-proven, ingredients and recipies. This produces a consistent product (which also forms the base for consumer recipies) and a loyal customer base. (No "New Coke" debacle or gradual deterioration of product quality over decades with this company.)
When I was working in retail about 5 years ago competitors of ours did the same. Our store name, their phone number.
That reminds me of why dial phones were invented.
Early telephone exchanges used an operator to connect all calls. You picked up the phone and this lit a lamp and sounded a buzzer at an operator's console in the central office. The operator pulgged a cable into a jac and talked to you, found out who you wanted to talk to, and plugged another cable into the other customer's jack (or a trunk to another operator) to hook you up. Similarly when you hung up, or (if the call needed some other modification and you "flashed" by flicking the hook switch).
Some businesses bribed unscrupulous operators to redirect their competitor's calls to them, stealiing some of their buiness (especially in high customer turnover businesses, where a large fraction of the calls were initial contacts.) There was much flap over this, of course.
One such customer - an undertaker - decided to attack this problem at its root. He also happened to be what we'd now call a hacker (in the "exceptionally competent technologist" sense). He developed the earliest version of a dial telephone system, and got one of the telephone companies serving his area to install it. Electromechanical stepper switches were not susceptable to bribery, problem solved.
Of course electromechanical stepper switches are also cheaper than even low-wage people. So dial systems caught on very quickly. You still needed operators for non-simple stuff, but a company handling the bulk of the calls mechanically needed far less of them, and when such service was available businesses switched over en masse.
Is this cell site actually intended to be connected back to the grid, or is it only for communication between phones connected to this one site?
Back to the grid. According to TFA:
That's a satellite modem that sells for about three grand. A bit over 0.4 mbps of encrypted data plus voice.
I find myself wondering if it can be combined with MIMO. That would be very cool.
It IS MIMO: the special case where:
- The base station antennas are widely separated.
- The data is mapped so each remote antenna gets a particular one-spectrum-channel-worth subset of the data stream (rather than several antennas getting several spectru-channels worth, but in the form of differently phased-and-weighted sums of several carriers with mixes of the data). This allows the remobe devices to work with a single antenna that can move around independently of the others.
There's no reason the signal can't be mapped so that a device with two or more sufficiently separated antennas can receive roughly as many spectrm-channels worth of bandwidth as it has antennas.
Might not be practical on a handset (at least not at frequencies below 3GHz), because there is not enough space to put adequate separation between antennas, but it could work well with tablets and other physically larger devices.
You called it. The separation doesn't need to be all that large (if the device is positioned near enough to the base stations that it "sees" adeqiate separation of the base antennas). But it does need to be at least in the ballpark of a quarter wavelength or more, even in the best of cases.
Spreading the component antennas of the MIMO base station out to different cell towers expands the area where MIMO tricks can be fully utilized in proportion - at the cost of requiring precise synchronization of local oscillators among the various antenna sites (and precise compensation for relative sway of the cell towers). But it doesn't require any changes at the remote end of the link - those antennas need the same separation for a given frequency and given perceived angular separation of the base antennas, regardless of the distance to the base antennas. (Spreading them further just means the remote can resolve smaller apparent angles, and thus work in more-than-spectrum mode further from the set of base stations.)
Sounds like, in the process of creating the virtual-reality hand model, they've also identified, extracted, and processed EXACTLY the signals necessary to operate a prosthetic.
This gives us the expectation that with the cybernetic prosthetic in place the phantom limb pain may not be a problem, as well.
(Of course that's presuming the summary is correct and it is confirmed.)
Steerable Null (alias DIDO or pCell) (the latter being steerable null with widely separated antennas) effectively multiplies the avaliable bandwidth by the number of base station antennas (by giving each remote a signal containig the full band's bandwidth directed to it, while the similar, simultaneous, signals to the other remotes cancel out).
See the article from last week: New 'pCell' Technology Could Bring Next Generation Speeds To 4G Networks.
Some posters were wondering what would be the driver for adopting it. This is it: There's no more spectrum being made - but this is a way to use it simultaneously multiple times without interference between the reuses.
Tesla vehicles are not green. The fact that it costs close to $100k should indicate that it is a very resource intensive product.
Actually it indicates that the early adopters are paying for building a car company and designing the car, not just the car itself, This is a proven model for new tech.
That "prissy pedal" makes the Model S go from 0 to 60 in 4 seconds and do a quarter mile in 12.5s. That's faster than a Porsche 911.
And that's much of why Tesla beats the competition.
Electrtic cars inherently COULD accelerate as much as possible given the coefficient of friction of tires on pavement. Electric motors generally have max torque at stall. All you need is a big enough motor and power supply. (What matters is being able to apply the necesary power during accelleration, which is a whole separate issue from cruising mileage.)
Unfortunately, other electric car manufacturers have been thinking "eco freeks in their underpowered compact and mini cars" and building underpowered electric powertrains. Martin Eberhard and Marc Tarpenning, along with the engineering team they assembled, did not make that mistake. Instead they designed a vehicle with the horsepower to have high performance.
The computation for DIDO (- steerable null) is a matrix multiply. Two additions + 2 adds times the product of the number of base station antennas and the number of active remotes.
Sorry, typo: Two multiplies and two adds. Ammortized per channel it's only an extra (multiply and add) * 2 * number of antennas for each I + Q sample of the generated waveform.
I'm seeing no mention of latency here. Running expensive computations to reconstuct the signal is going to add a considerable amount latency, which more or less eliminates video-chat applications.
Nope. It's done in a DSP, just like the computations that form the modulation/demodulation in the first place. It's blazingly fast (it HAS to be because you do it for every sample of the signal.)
The computation for DIDO (- steerable null) is a matrix multiply. Two additions + 2 adds times the product of the number of base station antennas and the number of active remotes. This is quite small compared to the number of computations to make the signals: An (inverse for transmit) FFT for each channel.
And this is a computation which gets more complex the mode devices you have in an area too.
(I'm not used to the tuchpad on my new laptop and seem to have actidentally posted mid-edit.)
The cure for this is to disable the trackpad (Alt+F7 on many laptops) and use the arrow keys or a mouse. WFM.
Thanks, but alt-f7 doen't do it on mine (which is running ubuntu 12.04 LTS>. Instead it emulates a left-click-and-hold to grab the object under the cursor.
I've got a little script that lets me toggle the enable/disable state but hadn't hooked up the mouse and activated it just then, so the touchpad was live.
I've tried to find an option for havig the the touchpad automagically go dead when the mouse is live (as windows has), but haven't found it in Ubuntu 12.04's unity. If anybody knows how to set that please let me know.
As I read this, DIDO is exactly "steerable null" with the antennas spread out.
Of course the antennas are spread out VERY FAR APART, as in to multiple sites using a central computation of the I/Q signal and synchronizing separate local oscillators at the remote sites. This results in "bubbles around", rather than "beams at", those cellpphones that are in among the antennas.
Isn't that the study that got debunked because it turmed out the bulk of the people rating astrology as scientific had misread it as "astronomy"?
If so, it might say more about Democrats' literacy than their their belief in astrology.
It would also be what is expected, given that the consituency of the Democratic party is heavily weighted toward groups of people who have been the victims of poor public schools.
It sounds like a logical extension of phased-array technology. Or, sort of how they do radiation cancer treatment with dozens of weak beams converging on one spot.
The former. Phased array is coherent (phase between sources is controlled and signals can cancel). Reverse-tomography radiation treatment is incoherent (phase is uncontrolled and energy only adds - but you make it strong in one place and as weak as practical elsewhere, or especially weak at other particularly radiation-sensitive sites.)
(I'd love to see a holographic tomography system, using, say, coherent x-rays. gamma rays, or even tunneling charged particles. B-) The closest I've heard of is the muon beam, where the muons decay at a particular distance from the accellerator that makes them, making a "bright star" spot on the end of a "dim rod")
Precisely. The equivalent computation is done in the receive pipe, so the base station system "hears" from each bubble separately, as well as "speaking" separately to each.
In fact it has to be done this way, or you'd only get the bandwidth multiplication in the outbound direction and the inbound direction would be sharing the bandwdith. (Fortunately the transmit and receive pathways are exactly duals of each other.)
The only similarity between DIDO and MIMO, as far as I understand it, is that they both use multiple antennas to send and receive separate data streams simultaneously. But their signal processing schemes are very different.
Not really. See below.
In broad strokes: DIDO does the signal processing (matrix math) on the transmitter side while MIMO does it on the receiver side.
Nope. MIMO does it at BOTH ends, to multiply the bandwidth between the two ends of the path by up to the number of antennas at the end with the smaller antenna count. The subchannels are, or can be, actually received by all the receive end antennas and sorted out in the receiver.
DIDO is MIMO with:
- The computation done so each remote-end antenna gets exactly one subchannel of the data (rather than a weighted and phase-shifted sum of all subchannels).
- The antennas at both ends very widely separated.
Sorting the signals this way allows the "remote end" to consit of many, independent, single-antenna devices, each with an independent data pipe as broad as the assigned spectrum. The wide separation of the antennas at both ends of the link makes a very large coverage area practical. Motion of the remote end devices just corresponds to a variation in the position and spacing of a remote-end MIMO device's antenna, requiring update of the parameters of the computation.
It's actually a phased array technique.
As is MIMO (which is more general but includes phased array as a special case when the number of antennas at one end of the link is one.)
However, it has significant challenges with timing, since now motion of the antenna becomes a huge factor (more than 1/4 wavelength in position uncertainty shits out the effect of an individual element.
At the customer end this is not a problem, since it's the difference of the paths to the various base antennas that matters. An easier way to visualize it is to notice that the technique creates bubbles where essentially only the desired channel is received (and from which the transmitted signal is the only one of the subscribers received in the corresponding uplink channel after the DIDO processing). As you move away from the middle of the bubble the signals to the other subscribers begin to rise from the noise floor - but that's slow enough that the DIDO computation can be updated. (I suspect that for phones in vehicles the "DIDO data center" will need to estimate the speed and direction of the target (i.e. the way the phases of the signals are changing) and continuously update the computation, interpolating between actual measurements.
Changes to the relative position of the base antennas is much more significant:
This will be fine for antennas that are solidly connected to buildings in the lower bandwidths, but useless for 1800/1900 MHz on towers. Yes, they do move that much.
But they're massive and move slowly - far below an audio rate (in essentially two dimensions, i.e. a subsonic stereo signal). So this can be included in the computation.
You'll want to feed the measurements of the antenna motion back to the DIDO center, which would be very low bandwidth. Doing the computation at the antenna site would require broadening the pipe to/from it to be as wide as the sum of the max bandwidth to ALL the subscribers rather than the max bandwidth to one. You'll also want to estimate the motion a little bit ahead on the base-to-subscriber side, to tune out the measurement/transmission delay of the antenna position info going to the cener and the computed waveforms going to the antenna.
Ideally the phones would have a similar mechanism but current 4G LTE phones do not. they are omnidirectional and broadcast noise in all directions, even if the antenna system is at a specific location.
That doesn't matter. You just do the equivalent computation on the returned signal. You "listen" separately to the individual bubbles, just as you send separately to them.
So you only need to do it at one end - the one where coordinating and combining the signals is practical.
(I'm not used to the tuchpad on my new laptop and seem to have actidentally posted mid-edit. Reposting the full version.)
Even though it is technically compatible with 4G you still have to deploy millions of new antennas. He may have invented the greatest wireless technology ever, but it's dead on arrival due to cost.
Actually it may be cheaper than buying more spectrum and putting in more equipment at the cell sites, since it doen't involve buying more spectrum.
It DOES involve putting in more cells. But far fewer than you'd need to put in to subdivide the cells, in the normal cellular paradigm, to get the same amount of bandwidth reuse multiplication.
Also: You can bootstrap it by putting the new computation into just the existing cells, letting you handle more connections than with the old scheme. (After that it's add more cells in the customary maner, with more bang per buck.) Not only that, you only need to do it in areas where you're already running out of base station capacity and starting to suffer service level problems due to oversubscription/congetioin. If replacing/upgrading the equipment in existing cells gives you more additional connections per buck than the alternatives, there's no adoption cliff at all.
Even though it is technically compatible with 4G you still have to deploy millions of new antennas. He may have invented the greatest wireless technology ever, but it's dead on arrival due to cost.
Actually it may be cheaper than buying more spectrum and putting in more equipment at the cell sites, since it doen't involve buying more spectrum.
It DOES involve putting in more cells. But far fewer than you'd need to put in to subdivide the cells, in the normal cellular paradigm, to get the same amount of bandwidth reuse multiplication.
Also: You can start it by putting the new computation into just the existing cells and handle more connections than with the old scheme. (After that it's add more cells in the customary maner, with more bang per buck.) If replacing/upgrading the existing cells gives you more
Modern LEDs and modern fluoresent tubes have comparable efficiency.
In more detail: LEDs have the potential to be about as much more efficient than switcher-ballasted flurorescents as such fluorescents are more efficient than generic incandescents. Actual LED fixtures have been improving and right now are at the point where they're matching and starting to edge past fluorescents.
Give 'em a few more years and LEDs should be substantially ahead of fluorescents. But this year they're just about tied.
(This is why I haven't replaced my fluorescents with LEDs yet. I plan to do it in a few more years, when my current stock of spares, enough for about one more bulb change, is used up. I'm abouit to switch the yard lghting, though, because the motion detector / fluorescent fixture combination has been problematic and is now failing.)
"Crossing the Chasm" is about more revenues by making a tech product more mainstream. It has nothing to do with cutting investments.
My objection to "Crossing the Chasm" is about a different issue: Cutting the early hires out of their equity positions by terminating the vesting of their stock options and possibly high salaries, so the company growth rewards go to the founders and the high officials rather than to the talent in the trenches that actually turned the hairbrained scheme into a functioning enterprise.
In the process the company typically dumps them before it is really ready to succeed without them. What they're doing for the company, and what information is in their heads but not well documented, isn't sufficiently visible to the executives - especially the new team that is trying to force the transition.
This zinger is in the last couple paragraphs of one of the chapters near the end of the book. (Unfortunately I don't have my copy handy or I'd give you the page number and quote.)
I've watched this happen at least three times here in Silicon Valley.
- Exec enthuses about the book.
- Couple months later the company lays off the early hires.
- Product development grinds to a near-halt as problems arise and don't get solved. Shipments are missed, or go out with major quality issues. Customer support fails.
- Within about a year the company goes belly-up.
Now it's just a bunch of MBAs trying to massage their stock price.
You got that right.
Algorithm:
- Get hired for a big salary and a LOT of stock options.
- Make the company appear more profitable by cutting off investments in the future to reduce costs now.
- Declare victory and what a great guy you are.
- Cash in the stock options and move on to a bigger company where you can repeat the process for even more money and reputation points. PROFIT!
- Your successor inherits the house of cards and takes the blame when it collapses a few years later.
The Harvard Business School has a reputation for graduates who use this algorithm.
Interestingly, boards of directors keep falling for this. (You'd think they'd look at what happens to companies candidates had "turned around" in the several years AFTER they left when evaluating CEO, COO, and CFO candidates. But apparently they usually don't.)
= = = =
Similarly, if a high company official starts enthusing about the book "Crossing the Chasm" and you're an early hire, cash any vested stock options and get out, before you and the other early hires are laid off. (Interestingly, they usually fire them too soon, when they're still key to the company's success, and the company usually falls INTO the chasm rather than crossing it.)
... it gets boring when repeated too often,
In case you don't get it: It's obviously intended to mimic a fake anti-malware product that spams people with ads for itself.
Yes, there is a product by that name, which is called out as a "borderline scam" - though mainly with claims that it does little (removing key-only registry entries), may cause trouble, and buying it can result in a periodic charge to your credit card that is difficult to stop.