After my last trip from Miami to Australia I got curious about the longest scheduled airline flight these days. It seems that as of last summer there's a Newark-to-Singapore flight, SQ 21, that lasts 18 hours and 35 minutes non-stop on a stripped-down (no first class!) Airbus 340-500. (The return, SQ 22, is a bargain at only 18:25.) The distance is 9534 statute miles (8285 nautical miles); the article is in error on this.
Of course, things were worse in the old days. There used to be 21-23 hour nonstop flights from London to the U.S. west coast on Lockheed L-1649A Super Constellation Starliners (see Starliner if you'd like to buy your own), but perhaps the all-time record is held by KLM:
"Perhaps the most famous day in the early history of KLM was October 1, 1931, when the airline began regular passenger service between Amsterdam and Batavia (now known as Jakarta in Indonesia) using Fokker F.12 aircraft fitted with four luxury seats. The trip lasted 10 entire days, including 81 hours of flying time. It was the longest regularly scheduled flight offered by any airline in the world."
You obviously do not fly across the Pacific very often. Realizing that you're flying at 550 mph when technology to fly at 1400 mph was introduced in the 1970s becomes really excruciating after about 10 hours into the flight.
To the point that you'd pay a significant surcharge to already be at your destination, asleep in your hotel room.
The high fuel consumption difficulty mentioned in TFA is what kept Concorde off of the Pacific routes; if that is resolved as the Japanese intend, I see a nice market for this plane.
The Motorola BPL system, the Powerline LV Solution, entirely avoids transmitting data over medium-voltage (MV) lines (the ones commonly seen along roads). It uses the Motorola Canopy wireless system for this link. The Powerline LV Solution only sends data over the neighborhood low-voltage (LV) lines, after the transformer, using HomePlug. This greatly reduces the potential for interference. Further, the Amateur Radio Relay League (ARRL), the organization of amateur radio operators in the U.S., was consulted during its development, had its interference issues addressed, and supports the Motorola Powerline LV Solution.
No, no, no...the lunar L1/L2 points. He means the L1/L2 points in the Earth/moon system, not the Sun/Earth system. The moon always has the same side to its L1/L2 points, so the problem you describe would not occur.
Already done. This alarm clock shoots the pieces of jigsaw puzzle up in the air when it goes off. To turn it off, you have to find the four pieces and then reassemble them on the clock.
I know the answer to your question, and was about to post a reply with an explanation, but before doing so I checked your web site so that I could learn more about my audience. I was hit with an attempt to change my browser's homepage (fortunately stopped by SpywareBlaster), as well as at least three (I lost count) pop under/over ads.
I became petulant at that point, and decided not to answer your question, after all--but I wanted you to know the reason why I didn't.
batteries are an additional weight, and once at the end of their lives, are an environmental nightmare
Lead acid batteries are an environmental nightmare? You should get out more - recycling or disposal of batteries is not difficult or even paticularly expensive. The consequences of having a leaky old car battery under the house are low, and the consequences of having a huge landfill full of them is far less than that of bacteria in copper mine tailings making sulphuric acid - the sort of thing we have had centuries learning to deal with.
...not to mention the fact that hybrid batteries are nickel-metal hydride, not lead-acid.
Spectrum allocation is a large, time-varying, multivariable optimization problem. This document is an outline of some of the service requests/requirements, and how they need to mesh with each other, present and future technology availability, and physical limitations (like attenuation due to water at 24 GHz). Note that this document is only U.S. interests; every other country has a similar list, and all have to be coordinated. It's like the guy who goes into a store with three lists: What he wants to buy, what he needs to buy, and what he can afford to buy. Compromise is the name of the game, and reasonable people will make reasonable tradeoffs differently.
The radar this article is discussing is a proposed future use of 24 GHz for collision-avoidance radar in passenger cars. 24 GHz is a popular frequency choice for short-range applications like this specifically because of the atmospheric attenuation. Note that the attenuation at 24 GHz, while higher than at other nearby frequencies, is still relatively low, only a few tenths of a dB per kilometer (although much higher in rain). This makes 24 GHz a good compromise for short-range devices on the Earth's surface, especially low-powered devices with very directional antennas pointed horizontally, away from satellites. (A better choice from this standpoint would be the oxygen absorption band at 60 GHz, and there is indeed another radar band there.)
Meterologists are merely expressing their concern over how their measurements will be corrupted if millions of car radars are in operation, and their cumulative power is enough to be detected by their sensors. My personal opinion, however, is that 24 GHz is too low of a frequency to make a market-successful car radar; the antennas are too big. I think 60 or 77 GHz is a better bet; if so, that would preserve 24 GHz for water vapor measurements.
In general, though, the interests of meterologists and others performing microwave sensing of the earth should be considered in the frequency allocation process; the publicity due to this article is one way of accomplishing this.
This happens in my area, too, and it's caused by the NIMBY attitude of people when they see a cell phone tower. Even if the cellular provider proposes a camouflaged tower (one that looks like a tree, etc.), they are beaten back by the pseudoscience wackos threatening health problems. They've even taken out existing towers ("Too close to the schools--think of the children!"), which I suspect is why you remember your MetroPCS phone fondly. As a result, my nearest cell tower is a zillion miles away and, like you, I have no coverage indoors.
ZigBee's strategy has always been to make the standard open (meaning available for free download on the web for noncommercial use, academic study, etc.), while remaining proprietary (meaning that one must be a member of the ZigBee Alliance to use the spec in commercial products).
You're right, IEEE 802.15.4 does not encompass any mesh routing. IEEE 802 standards cover only the PHY and MAC layers of the OSI stack, so networking is not included. However, 15.4 was designed to support such services, and their specification is one of the main functions of the ZigBee specification. The ZigBee specification describes a multihop routing protocol that has been tested in large networks on products made by multiple vendors. You won't have to write your own routing protocol.
After the Bluetooth debacle, ZigBee members were pathological in their desire for interoperability--it is one of the mantras heard at every meeting, and drove the many interoperability fests that were held in 2004. It was felt that, whatever mistakes they may make, they should at least make new mistakes--repeating the mistakes of Bluetooth would be foolish, indeed.
Philips has been a world-class R&D company for a long time. Philips Research was established in 1914, and has contributed much, from the invention of the pentode vacuum tube (valve) by Tellegen in 1929 to the audio cassette in the 1960s and their more modern work developing CDs and DVDs.
The fire has been lit under IBM and other corporate research organizations for a long time.
The jet liner to which you refer, I think, is the Gimli glider which, through a forehead-slapping number of independent goofs, ambiguities, and misunderstandings made by a frighteningly large number of people, ran out of fuel over Cananda in 1983.
IEEE Spectrum has a nice article on this near-debacle. The problem was that the tests performed did not consider that the received data rate, in addition to the carrier frequency, would be affected by Doppler, and the receiver would lose bit synchronization.
The full system test, which would have detected the problem, was not performed because--wait for it--they wanted to save money.
Hybrid cars do not have more maintenance than regular ICE cars. Check the suggested maintenance schedules of the Prius vs. that of, say, a Camry. Hybrids have some more "electric stuff," but since it's electric and electronic, it needs little or no maintenance. Also keep in mind that the Prius' ICE and electric motor interface replaces the conventional transmission, so the interface can hardly be considered extra.
I agree that the economics are about a wash, so the real point is, why not get a hybrid--especially since you get other nice features, like a tax deduction, driving in HOV lanes when you're alone, silence at stoplights, plus the knowledge that you're producing far less pollution (at least in the case of the Prius) than almost everything else on the road? Why wait for your economic all-electric car that isn't here?
(n.b.: As a matter of discourse, to convince others of the validity of your economic argument it would be best if, after saying that you can save money with an all-electric car, don't say in the same paragraph that the big problem with them is their batteries are very expensive.)
In Don Garlits' Museum of Drag Racing there's a top fuel dragster he developed that used a large tank of compressed air to drive the engine blower (supercharger). The idea was that driving the supercharger was actually a large load on the engine, and that if he could power the supercharger from something else, more power would be available to the rear wheels.
Unfortunately, the design wasn't successful; IIRC Don doesn't say exactly why, but I suspect a problem would be regulation of the compressed air power to drive the supercharger; most power is available from the air tank at the start of the run, while most power is needed to drive the blower at the end of the run.
Plus, I suspect the NHRA would have some regulatory comment on the whole affair.
The electric system alone will drive the Prius at 42 miles per hour or less, when the battery is at a nominal to high state of charge. Range in this mode is one to two miles, depending on driving conditions and other internal loads on the electrical system, as the parent states.
Note also that, while it still does not have an external charger, the Prius sold in Europe has an "EV-only" switch that enables the car to be operated as an electric-only vehicle. Prius sold in the US do not have this switch, and are hybrid only.
Almost correct. You need AES-128 authentication and message integrity checking, not encryption, but ZigBee has both. Encryption merely makes the message private, but authentication ensures that the source address wasn't spoofed, and integrity checking ensures that it hasn't been corrupted or modified before reaching the recipient.
BTW, the IEEE 802.15.4 spec is available for free download.
Slashdot Mirror
It's really easy: It's "his", hers", and "its". Even a flower knows!
--cycling through grammar Nazi mode. Please wait.
After my last trip from Miami to Australia I got curious about the longest scheduled airline flight these days. It seems that as of last summer there's a Newark-to-Singapore flight, SQ 21, that lasts 18 hours and 35 minutes non-stop on a stripped-down (no first class!) Airbus 340-500. (The return, SQ 22, is a bargain at only 18:25.) The distance is 9534 statute miles (8285 nautical miles); the article is in error on this.
Of course, things were worse in the old days. There used to be 21-23 hour nonstop flights from London to the U.S. west coast on Lockheed L-1649A Super Constellation Starliners (see Starliner if you'd like to buy your own), but perhaps the all-time record is held by KLM:
You obviously do not fly across the Pacific very often. Realizing that you're flying at 550 mph when technology to fly at 1400 mph was introduced in the 1970s becomes really excruciating after about 10 hours into the flight.
To the point that you'd pay a significant surcharge to already be at your destination, asleep in your hotel room.
The high fuel consumption difficulty mentioned in TFA is what kept Concorde off of the Pacific routes; if that is resolved as the Japanese intend, I see a nice market for this plane.
Yes, this is a dupe of a dupe, although the means by which the lens is focused (mechanical motion vs. electrowetting) is different.
Interestingly, this allows us to complain more efficiently, as we can merely cite our original complaints, instead of having to type them in again.
Another technical advance brought to you by your friendly Slashdot editors!
The Motorola BPL system, the Powerline LV Solution, entirely avoids transmitting data over medium-voltage (MV) lines (the ones commonly seen along roads). It uses the Motorola Canopy wireless system for this link. The Powerline LV Solution only sends data over the neighborhood low-voltage (LV) lines, after the transformer, using HomePlug. This greatly reduces the potential for interference. Further, the Amateur Radio Relay League (ARRL), the organization of amateur radio operators in the U.S., was consulted during its development, had its interference issues addressed, and supports the Motorola Powerline LV Solution.
No, no, no...the lunar L1/L2 points. He means the L1/L2 points in the Earth/moon system, not the Sun/Earth system. The moon always has the same side to its L1/L2 points, so the problem you describe would not occur.
Already done. This alarm clock shoots the pieces of jigsaw puzzle up in the air when it goes off. To turn it off, you have to find the four pieces and then reassemble them on the clock.
My sister had 4 daughters in 3 years. It's been done already.
That would be unlicensed operation in the TV bands, now being standardized by IEEE 802.22, the newest 802 working group.
...except now it says, "loss of data." I hope that's just due to a communications failure (perhaps LOS while over the atlantic?).
I know the answer to your question, and was about to post a reply with an explanation, but before doing so I checked your web site so that I could learn more about my audience. I was hit with an attempt to change my browser's homepage (fortunately stopped by SpywareBlaster), as well as at least three (I lost count) pop under/over ads.
I became petulant at that point, and decided not to answer your question, after all--but I wanted you to know the reason why I didn't.
Spectrum allocation is a large, time-varying, multivariable optimization problem. This document is an outline of some of the service requests/requirements, and how they need to mesh with each other, present and future technology availability, and physical limitations (like attenuation due to water at 24 GHz). Note that this document is only U.S. interests; every other country has a similar list, and all have to be coordinated. It's like the guy who goes into a store with three lists: What he wants to buy, what he needs to buy, and what he can afford to buy. Compromise is the name of the game, and reasonable people will make reasonable tradeoffs differently.
The radar this article is discussing is a proposed future use of 24 GHz for collision-avoidance radar in passenger cars. 24 GHz is a popular frequency choice for short-range applications like this specifically because of the atmospheric attenuation. Note that the attenuation at 24 GHz, while higher than at other nearby frequencies, is still relatively low, only a few tenths of a dB per kilometer (although much higher in rain). This makes 24 GHz a good compromise for short-range devices on the Earth's surface, especially low-powered devices with very directional antennas pointed horizontally, away from satellites. (A better choice from this standpoint would be the oxygen absorption band at 60 GHz, and there is indeed another radar band there.)
Meterologists are merely expressing their concern over how their measurements will be corrupted if millions of car radars are in operation, and their cumulative power is enough to be detected by their sensors. My personal opinion, however, is that 24 GHz is too low of a frequency to make a market-successful car radar; the antennas are too big. I think 60 or 77 GHz is a better bet; if so, that would preserve 24 GHz for water vapor measurements.
In general, though, the interests of meterologists and others performing microwave sensing of the earth should be considered in the frequency allocation process; the publicity due to this article is one way of accomplishing this.
Check your renters'/homeowners' associations.
This happens in my area, too, and it's caused by the NIMBY attitude of people when they see a cell phone tower. Even if the cellular provider proposes a camouflaged tower (one that looks like a tree, etc.), they are beaten back by the pseudoscience wackos threatening health problems. They've even taken out existing towers ("Too close to the schools--think of the children!"), which I suspect is why you remember your MetroPCS phone fondly. As a result, my nearest cell tower is a zillion miles away and, like you, I have no coverage indoors.
ZigBee's strategy has always been to make the standard open (meaning available for free download on the web for noncommercial use, academic study, etc.), while remaining proprietary (meaning that one must be a member of the ZigBee Alliance to use the spec in commercial products).
You're right, IEEE 802.15.4 does not encompass any mesh routing. IEEE 802 standards cover only the PHY and MAC layers of the OSI stack, so networking is not included. However, 15.4 was designed to support such services, and their specification is one of the main functions of the ZigBee specification. The ZigBee specification describes a multihop routing protocol that has been tested in large networks on products made by multiple vendors. You won't have to write your own routing protocol.
After the Bluetooth debacle, ZigBee members were pathological in their desire for interoperability--it is one of the mantras heard at every meeting, and drove the many interoperability fests that were held in 2004. It was felt that, whatever mistakes they may make, they should at least make new mistakes--repeating the mistakes of Bluetooth would be foolish, indeed.
I wonder how Philips feels about it.
From the same news source, there may be other reasons for IM's popularity. . . .
Philips has been a world-class R&D company for a long time. Philips Research was established in 1914, and has contributed much, from the invention of the pentode vacuum tube (valve) by Tellegen in 1929 to the audio cassette in the 1960s and their more modern work developing CDs and DVDs.
The fire has been lit under IBM and other corporate research organizations for a long time.
I was with you until you messed up and supplied us the gory details. Blearghh--I would happily pay $1200 to avoid all that.
The jet liner to which you refer, I think, is the Gimli glider which, through a forehead-slapping number of independent goofs, ambiguities, and misunderstandings made by a frighteningly large number of people, ran out of fuel over Cananda in 1983.
IEEE Spectrum has a nice article on this near-debacle. The problem was that the tests performed did not consider that the received data rate, in addition to the carrier frequency, would be affected by Doppler, and the receiver would lose bit synchronization.
The full system test, which would have detected the problem, was not performed because--wait for it--they wanted to save money.
Hybrid cars do not have more maintenance than regular ICE cars. Check the suggested maintenance schedules of the Prius vs. that of, say, a Camry. Hybrids have some more "electric stuff," but since it's electric and electronic, it needs little or no maintenance. Also keep in mind that the Prius' ICE and electric motor interface replaces the conventional transmission, so the interface can hardly be considered extra.
I agree that the economics are about a wash, so the real point is, why not get a hybrid--especially since you get other nice features, like a tax deduction, driving in HOV lanes when you're alone, silence at stoplights, plus the knowledge that you're producing far less pollution (at least in the case of the Prius) than almost everything else on the road? Why wait for your economic all-electric car that isn't here?
(n.b.: As a matter of discourse, to convince others of the validity of your economic argument it would be best if, after saying that you can save money with an all-electric car, don't say in the same paragraph that the big problem with them is their batteries are very expensive.)
In Don Garlits' Museum of Drag Racing there's a top fuel dragster he developed that used a large tank of compressed air to drive the engine blower (supercharger). The idea was that driving the supercharger was actually a large load on the engine, and that if he could power the supercharger from something else, more power would be available to the rear wheels.
Unfortunately, the design wasn't successful; IIRC Don doesn't say exactly why, but I suspect a problem would be regulation of the compressed air power to drive the supercharger; most power is available from the air tank at the start of the run, while most power is needed to drive the blower at the end of the run.
Plus, I suspect the NHRA would have some regulatory comment on the whole affair.
The electric system alone will drive the Prius at 42 miles per hour or less, when the battery is at a nominal to high state of charge. Range in this mode is one to two miles, depending on driving conditions and other internal loads on the electrical system, as the parent states.
Note also that, while it still does not have an external charger, the Prius sold in Europe has an "EV-only" switch that enables the car to be operated as an electric-only vehicle. Prius sold in the US do not have this switch, and are hybrid only.
Almost correct. You need AES-128 authentication and message integrity checking, not encryption, but ZigBee has both. Encryption merely makes the message private, but authentication ensures that the source address wasn't spoofed, and integrity checking ensures that it hasn't been corrupted or modified before reaching the recipient.
BTW, the IEEE 802.15.4 spec is available for free download.