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User: john.r.strohm

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  1. Re:Thank goodness the Enterprise is aerodynamic. on Star Trek Enterprise Tested to Mach 5 · · Score: 1

    I dunno. Here's an interesting reference.

    AIM-2002-017
    Author[s]: Jack Wisdom

    Swimming in Space-Time

    November 2002

    ftp://publications.ai.mit.edu/ai-publications/20 02 /AIM-2002-017.ps

    ftp://publications.ai.mit.edu/ai-publications/20 02 /AIM-2002-017.pdf

    Cyclic changes in the shape of a quasi-rigid body on a curved manifold can lead to net translation and/or rotation of the body in the manifold. Presuming space-time is a curved manifold as portrayed by general relativity, translation in space can be accomplished simply by cyclic changes in the shape of a body, without any thrust or external forces.

    So maybe they aren't all that far off.

  2. RFID 101 on And They Shall Know You By Your Books · · Score: 3, Informative

    Sometimes, people panic when there is no reason to do so.

    Background: Texas Instruments invented RFID tags, as TIRIS (Texas Instruments RF Identification System, or some such). I was working at TI at the time, and TI is *VERY* good about blowing their own horn internally on new unclassified gadgets, in the hopes that other TIers will come up with interesting new applications for the new gadgets.

    The RFID transponder is a fairly clever device. You put in a fairly strong low-frequency RF field, and it rectifies enough power from the field to power a very limited microcontroller and transmitter, just enough to transmit a unique serial number that is burned into the transponder at manufacture time.

    The transponder has a VERY limited range, because of the power limitations.

    The serial number is NOT customer-programmable, for very good reasons. This lets them guarantee that every transponder is UNIQUE, and makes it IMPOSSIBLE to confuse your car keys with someone's missing prize bull when you go to the rodeo.

    The transponder has NO intelligence, beyond the ability to squeak out the burned-in serial number when it finds itself in a power field. That's it. The host computer has to convert that serial number into something useful.

    The specific design goal was for something that could be read WITHOUT CONTACT, as it walked (or drove) past a sensing point. The original goal was an implantable device, for livestock ID. One of the early applications was a drive-by tolltag.

    The only way you are going to be tracked in real-time by your RFID-equipped library books is if the government literally blankets the country in tolltag gates.

  3. Re:A thinly veiled political rant, actually on The Surprising Benefits of Being Unemployed · · Score: 1

    Actually, there is a very interesting analysis over on http://www.jerrypournelle.com that suggests that knocking Iraq over, and rebuilding it, is in fact a very good move for the US.

    Take a look at it.

  4. Re:Not such a bad idea on Microsoft wants Automatic Update for Windows · · Score: 1

    There's just one LITTLE problem with that theory.

    If the machine stopped working, IT NOW ISN'T WORKING AND YOU CAN'T DOWNLOAD THE PATCH TO IT!

    "Auto update" is treating the symptom, not the disease. The disease is Microsoft's apparent inability to write reliable, secure code, as evidenced by their track record on exploitable buffer overrun vulnerabilities.

    Brethren and sistren, do you realize that, by the simple expedient of outlawing temporary buffers on the stack, Microsoft could kill most of their buffer overrun stack smashing problems ALL AT ONCE?

  5. Re:Doesn't get much clearer than this. on Cringely On Electronic Tapping · · Score: 1

    Maybe you should READ Ms. Coulter's book before you go off so smugly certain she's wrong.

    She goes to a great deal of trouble to document her work, backing up every single point with cold, hard, unpleasant (to Liberals, anyway) facts.

    Of course, since when were slashdotters ever known for being influenced by facts?

  6. Re:Oh, those nasty unions... on Working Hard? · · Score: 1

    Time for a history lesson.

    The labor unions generally get the credit for the 40-hour week and the 8-hour day, but that isn't what made it happen.

    What made it happen was that the first companies that tried it, back when 12-14 hours was the normal workday, saw their scrap and rework rates, and their injury rates, fall dramatically, which translated into an immediate and dramatic rise in their profits. The 8-hour day paid for itself, and then quite a bit.

    If the early adopters hadn't made significant profits off of the reduced workday, it would never have been adopted by the followers.

  7. MOD PARENT UP!!! on IT at the CIA · · Score: 1

    This is PRECISELY correct.

    By definition, you WILL NOT learn about the CIA's successes, because they are CLASSIFIED and they will STAY that way until everyone involved, and everyone whose involvement derives from it, is long since dead.

  8. Re:Probability of punishment? on When Bad Software Can Kill · · Score: 1

    Unfortunately, this one was NOT caught before anyone was hurt.

    Bob Raimo. Mitch Skaggs, and a few other guys are crippled for life because of those computers.

    I know Raimo, slightly. He was one of the good guys. He almost became one of my regulator technicians, when it was getting hard to find a good Beuchat tech in Dallas. (You better believe you are trusting your life to your regulator technician: if he screws up, you stop breathing.)

  9. Re:Population density and other requirements on Creating Car Free Cities · · Score: 1

    And yes, you can stack things on top of each other, to get more space, but that increases the cost of the stacked buildings A LOT. There is a REASON why single-story tiltwall strip mall construction is so popular in the areas where the land is available: it is CHEAP.

  10. Population density and other requirements on Creating Car Free Cities · · Score: 2, Interesting

    1 million people in 100 square miles is 2788 square feet per person, TOTAL.

    Not all of that space will be available to each person, of course. Some of it MUST be reserved for roadways, or helipads, or whatever, for those times when it is absolutely critical (as in life-and-death critical) to move someone, with equipment, from point A to point B in the absolute minimum possible time. (They're called "ambulance rides to trauma centers". They happen. I've done it. It really was an emergency: I stopped breathing about the time they were rolling me through the ER doors. I woke up, in ICU, on a respirator, a full week later.)

    There are still going to be requirements for hospitals. There are still going to be requirements for schools. There are still going to be requirements for entertainment venues.

    ALL OF THOSE USES COME OUT OF THAT 2788 sq.ft. per person.

    There are still going to be requirements to haul equipment from point A to point B. You will still need roads, and you will still need powered cargo vehicles.

  11. Re:Read these *drafts* more carefully on Broad Bills to Protect 'Communications Services' · · Score: 1

    You need to take your own advice.

    The key phrase is "with the intent to harm or defraud". This implies a requirement on the part of the prosecutor (in a criminal case) or the plaintiff (in a civil case) to prove said intent.

    The kicker is that there is language later in the bill that creates a PRESUMPTION of intent, if the defendant does not respond within 30 days to a letter from the communications service provider alleging a violation.

    That provision HOPEFULLY would not stand up to Constitutional scrutiny.

  12. Re:Ouch on Broad Bills to Protect 'Communications Services' · · Score: 2, Informative

    Yes. What he said.

    The guy who originally wrote the Racketeering in Corrupt Organizations (RICO) law deliberately wrote the bill as broadly as he could, despite warnings from colleagues, because he believed that prosecutors could be trusted to use reasonable discretion and judgement and only use the bill for the intended purpose, to wit, going after organized crime.

    He reportedly has a great deal of difficulty sleeping at night these days, as he contemplates just how much carnage his baby has wrought. The prosecutors have had a field day using his tactical nuclear weapon as an all-purpose flyswatter.

  13. Re:Why would I want to move to 64 bit computing? on Are We Not Ready For 64-Bit? · · Score: 1

    No, really big file operations will not be much faster.

    The limiting factor on file operations is not number of address pins, but the rotational speed of the disk platter. For example, 7200 rpm means one track every 8.333 milliseconds, and there ain't squat you can do in the processor about it.

    Hopefully, we'll see some HONEST physical specs out of the disk drive manufacturers, and maybe we'll see some seriously intelligent hard drive controllers that can snarf or spray a complete cylinder at a time, in parallel, across all the heads at once.

  14. This will ruin my karma, but... on Slashback: Privacy, Spectrum, Location · · Score: 5, Informative

    The statement about AM is flat-out wrong.

    Do the fscking trig.

    Consider a sinewave modulating signal. Let c be the carrier frequency, and m be the modulating frequency. Recall that cos(u) varies between -1 and 1. We want the modulating control signal to vary between 0 and 1, so the modulator is 1/2(1+cos(m)).

    We use cos(u) because it simplifies the key trick in the derivation. OBVIOUSLY, it is just a phase shift to do it in sin(u).

    Then the fundamental equation of AM is

    f(t) = 1/2(1+cos(m))cos(c) (1)
    = (1/2 + 1/2cos(m))cos(c)
    = 1/2 cos(c) + 1/2 cos(m)cos(c) (2)

    The first term is the carrier wave. Observe that it carries half of the input power and NONE of the modulating signal.

    Recall from basic trig

    cos(u+v) = cos(u)cos(v) - sin(u)sin(v)
    and
    cos(u-v) = cos(u)cos(v) + sin(u)sin(v)

    Then
    cos(u+v) + cos(u-v) =
    (cos(u)cos(v) + cos(u)cos(v)) +
    (sin(u)sin(v) - sin(u)sin(v))
    which simplifies to
    cos(u+v) + cos(u-v) = 2 cos(u)cos(v)
    Or
    cos(u)cos(v) = 1/2(cos(u+v)+cos(u-v))

    That looks familiar. Recall (2)

    f(t) = 1/2 cos(c) + 1/2 cos(m)cos(c) (2)

    Substituting

    f(t) = 1/2 cos(c) + 1/2(1/2(cos(m+c)+cos(m-c)))
    = 1/2 cos(c) + 1/4 (cos(m+c) + cos(m-c))

    And there you have it. You have a carrier wave, and you have two sidebands, and the bandwidth of the whole thing is twice the modulating frequency.

    The next step is to observe that the Fourier theorem applies and is carried straight through, and so ANY modulating signal will generate two sidebands, one above and one below the carrier wave, each preserving the harmonic content of the modulating signal, but with one reversed in frequencies.

    Your explanation of FM is just as bad. I'm not going to do the derivation, because it is MUCH messier, involving very ugly Bessel functions, and I don't have my textbook handy.

    You can reduce the bandwidth of an FM signal, but you lose fidelity.

    You can reduce the bandwidth of an AM signal by band-limiting the input audio information, which is routinely done in voice communications gear: the full audio spectrum goes up to NOMINALLY 20 kHz, but the useful speech formants are pretty much all found between 300 Hz and 3 kHz.

    You can suppress the AM carrier wave, and you can suppress one of the sidebands. This is also routinely done, in single sideband communications. This involves loss of redundancy and loss of easy tuning, which in turn makes careful tuning much more important: any mistuning comes out as distortion.

  15. Two birds with one stone on Building Your Own Glowing Cyber-Balls? · · Score: 2, Informative

    Motorola currently has a design contest going with
    their MC68HC908QT4 8-bit microcontroller. This
    puppy is an 8-pin DIP, FLASH EEPROM programmable,
    and the pins appear to be PWR, GND, and 6 I/O
    pins. (One of them may be a clock, or it may be
    set up to accept a clock if you give it one.)

    Start at http://www.circuitcellar.com for details.

  16. Zingers in the proposed bill on Texas Bill Would Require Open Source Consideration · · Score: 5, Interesting

    There is a beautiful zinger in the first section of the proposed bill. Paraphrasing slightly:

    "For all new software acquisitions, a state agency shall avoid the acquisition of products that are known to make unauthorized transfers of information to, or permit unauthorized control of or modification to the state government's computer systems by, parties outside the control of the state government."

    If memory serves me, Microsoft's click-wrap licenses, and the Windows XP activation process, and their auto-update processes, do EXACTLY that sort of thing.

    Also note that the bill's definition of "open source software" requires "(E) freedom to make and distribute copies of the software; and (F) freedom to modify the software and to distribute the modified software under the same license as the original software."

    This would seem to exclude Microsoft's "Shared Source" hogwash.

  17. Re:Two common sense things they can do now on NASA To Try To Resume Flights By Fall · · Score: 1

    1. Unmanned prox ops are HAIRY. Screw up EVEN SLIGHTLY and you ding the orbiter with your inspect-o-bot. Where you previously had an undamaged bird, you now have a real problem.

    It would be far simpler to task an NRO satellite to image the Shuttle. It is now coming out that someone at NASA queried NRO about doing this for Columbia. NRO advised NASA that they could do it, but NASA would have had to ask them to do it on a priority basis. The NASA program manager declined to make the request, and the rest is history.

    In this particular case, nothing could have been done. Columbia was not carrying space suits, as no EVA was planned for the mission.

    Oh, and as for the idea of keeping a second Shuttle on standby: Forget it. NASA can only fly one bird at a time. They routinely have to cannibalize parts from the other birds to build one flyable Shuttle. In fact, they almost had to scrub one flight, until they found that they had a part from the Challenger wreckage that was usable.

    2. It ain't possible. It takes a LOT of energy to do an orbital plane-change maneuver. A "detour" to the space station would require at least one, probably two such. There isn't anywhere near enough OMS fuel aboard the Shuttle to do it.

  18. Re:has the international space station had it's ti on Slashback: Intuit, Telemetry, Meetup · · Score: 5, Interesting

    Some years ago, at 1 AM on a weeknight, on a back-country road on the south side of Austin, I saw the most incredible traffic jam I've ever seen.

    I live in Dallas. I've driven in Los Angeles. I've seen some traffic jams.

    What made this incredible is that it was also the politest traffic jam I've ever seen. Everyone was having a good time, no one was arguing, no horns were honking.

    That road ran by Bergstrom Air Force Base, by the ramp. The Shuttle transporter 747, with a Shuttle on its back, was sitting on the ramp overnight. Everyone in that traffic jam wanted to see the Shuttle.

    I wish I'd taken some pictures of the crowd, to give to the people who MISTAKENLY believe that "nobody is interested in space." There sure were a lot of "nobody" out on that road at 1 AM that night.

  19. Re:Custom SETI@Home chip. on Retro-Computing with FPGAs · · Score: 1

    Some years ago, while I was working briefly on a radar project, I remember seeing dedicated FFT chips that were damn fast.

    I can't find them now, and I don't remember who made them. They were a specialized niche, obviously.

    Anyone else remember these? Know where I could find them?

  20. Look a little closer on 10 Techno-Cool Cars · · Score: 1

    The current-generation Corvette beats just about everything else. The car has full-time fly-by-wire, computer-controlled engine and suspension, and absolutely superb performance and handling qualities.

    And it all works, RELIABLY.

  21. Re:Computer keypads vs. telephone keypads on Keyboard Layouts for the 21st Century? · · Score: 1
    Practice. People who used adding machines at that time generally used them a LOT, to the point that the patterns get hardwired into the brain. (Same thing with touch typists.)

    The story I heard is that Bell did a lot of human factors studies, being careful NOT to select a disproportionate number of adding machine users, and learned that accuracy AND PREFERENCE favored the 123-top arrangement.

    The interesting question would be why the adding machine manufacturers all standardized on the 123-bottom arrangement.

  22. Why did they continue? on The Making of the Atomic Bomb · · Score: 1

    Time for a brief history lesson. 1914-1918 World War I, started out of Germany. 1941-1945 World War II, started out of Germany. Two world wars, twenty years apart, both started out of Germany. I'd speculate that they didn't want to see World War III, in another twenty years, also started out of Germany.

  23. Re:Yes, it's legal on Circuit Court Okays Vote Swapping Site · · Score: 1
    Actually, that "flaw" is a feature.

    The purpose of the Electoral College was to force the candidates to do well across the entire United States. A system that just counted popular votes basically would have allowed a few very populous states to control everything. A system that just counted state votes would have allowed small, sparsely-populated states to run roughshod over large, populous ones.

    The Electoral College was a compromise, precisely the same compromise as was made with the two houses of the Congress.

    There was a wonderful U.S. map, showing the 2000 Presidential election results by county, that made the rounds after the dust had settled. That map did an outstanding job of explaining why we have the Electoral College.

  24. Can you say "lawsuit"? on SDF Punted, Due to DDOS · · Score: 0, Interesting

    Disclaimer: I am not a lawyer, and I do not play one on TV. Having said that, based on a quick read of the contract, NWLink is on very shaky legal grounds, and SDF looks to have a very solid case against them.

  25. Dollar costs on Open Source Requirements Management Systems? · · Score: 2, Insightful
    You say that you have issues with spending $1200-$10K per seat for a requirements package.

    Let me point out that your company is already planning on spending, fully-burdened with overhead, nominally $250,000 per seat on your developers. That is salary, benefits, cost of office space, cost of lights, cost of PCs, secretarial support, janitorial support, bathrooms, water fountains, time spent perusing the lastest zero-information-content puffery from the Board of Directors, everything. $1200-$10K per seat is pretty small potatoes by comparison.

    Having said that, I suggest you take another look at your wish list and ask yourself how often you REALLY are going to *USE* all those bells and whistles. Do you NEED them, or do you just WANT them? Do you NEED one-button brass-band-Mozart, or do you just need to be able to pull the data out OCCASIONALLY for a right-now CEO presentation?

    Your payoff occurs when you automate the things that happen every day. Spending a fortune to automate the things that never happen is wasting time and money.