×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

Comments

top

This 1981 BYTE Magazine Cover Explains Why We're So Bad At Tech Predictions

dtmos Most unlikely technology in 1981: Handheld GPS (263 comments)

I always thought the most unlikely technological development in my lifetime was the handheld GPS device. It would be "most unlikely" because it required tremendous, simultaneous, and largely unforeseen advances in several different technologies, each of which was hard to predict in 1981. The list is at least:

1. Low power, low voltage, low noise L-band receivers, sensitive enough to be compatible with the weak signal coming from the internal antenna of a handheld device;
2. Stupendous amounts of digital signal processing, also at low power and low voltage;
3. Digital map databases of (substantially) every road in the world, accurate to a few meters;
4. A substantially world-wide, wideband wireless data link to get the digital map into the handheld device in the first place;
5. Low power, low voltage, high resolution, multicolor flat panel displays;
6. Gigabytes of low power, low voltage data storage memory; and
7. High energy density, high power density batteries capable of supplying the whole thing.

And, perhaps most impressive of all, the manufacturing technology to make all of the above small enough to fit in a handheld device, at a price low enough to sell by the zillions.

Of the list above, probably only #2 could have been predicted, and then only if one were willing to extrapolate the then-relatively-new Moore's Law by a very large amount. (Recall that Mead and Conway had only written their Introduction to VLSI systems the previous year; until then it was not clear that such complex chips could even be designed on human time scales, let alone built for a profit.)

The fact that a handheld GPS device is now an anachronism, since the technology is now small enough and low-power enough to be integrated into other handheld devices, like smart phones, pleases me no end.

yesterday
top

Mathematicians Use Mossberg 500 Pump-Action Shotgun To Calculate Pi

dtmos a bunch of dead zombies (303 comments)

AND a bunch of dead zombies.

What's a dead zombie? Is this some kind of recursion?

(Getting old has a lot of advantages, but one of the disadvantages is that it's harder to keep track of popular memes. I mean, I never understood the whole "vampire" thing, and now we're on to zombies. What's next?)

2 days ago
top

Data Mining the Web Reveals What Makes Puzzles Hard For Humans

dtmos Re:Idiotic summary (44 comments)

The "they" in the quoted line refers to people, not computers. It's the people picking the method (poorly).

The issue with Sudoku is that easy and difficult puzzles can have the same number of boxes to fill.

about two weeks ago
top

Data Mining the Web Reveals What Makes Puzzles Hard For Humans

dtmos Value (44 comments)

Somewhere I read an article by a guy who makes and sells Sudoku puzzles to newspapers. He explained that the value of providing the puzzle was near zero, since anyone with a computer could easily generate thousands of them, and anyone without a computer could get them from any number of sources. The value of his service, and the reason newspapers paid him to provide the puzzle, he said, was that he provided an accurate difficulty estimate to the puzzle. People attempting, and failing to solve, a difficult puzzle rated "easy", and people quickly solving an easy puzzle rated "difficult", were dissatisfied, and complained. People that had the experience they expected -- easy puzzles quickly solved, hard puzzles solved only with difficulty -- were much more satisfied.

The result was, newspaper editors got fewer complaints using his puzzles than they did from his competitors, so they bought from him.

He said he spent far more time tweaking his difficulty-rating algorithm than he did his software that generated the puzzles themselves -- since that was what kept him in business.

about two weeks ago
top

One Person Successfully Removed From US No-Fly List

dtmos Older than that (286 comments)

[I]t's actually a very strategic piece of property that dates back to the cold war.

It's actually older than that. The US has been there since the Cuban-American Treaty of 1903.

about three weeks ago
top

$30K Worth of Multimeters Must Be Destroyed Because They're Yellow

dtmos Re:Baloney (653 comments)

The fact that there are lots of yellow multimeters for sale in the US is not relevant, for that could mean either (a) they are knockoffs, and Fluke is losing the battle against the counterfeit products; or (b) Fluke has a successful side business licensing its trademark. (n.b.: Multimeters were almost uniformly black -- e.g., the Simpson 260 -- in the years before Fluke introduced its first yellow model, in the 1980s. It was very distinctive at the time.)

And you should exercise caution in what you encourage in others: The issue at hand is a trademark, not a patent, and I think you'll find, if you look up the trademark registration certificate (the controlling legal document), that it very specifically mentions the color yellow.

about a month ago
top

$30K Worth of Multimeters Must Be Destroyed Because They're Yellow

dtmos Baloney (653 comments)

Any "hobbyist electronics retailer" attempting to sell a multimeter in the US knows -- or should know -- what a Fluke multimeter looks like, and any businessman or businesswoman knows -- or should know -- that there will be problems trying to sell a product that looks like the product with a dominant share of the market.

Also, you don't need "an army of consultants or attorneys to find this information." Trademarks are freely available from the USPTO web site, in searchable form. Anybody can look them up.

Finally, most business contracts between a manufacturer and a distributor will have an indemnification clause, in which the manufacturer warrants that the product has no intellectual property issues and, should a claim be made against the distributor, the costs associated with such claims will be borne by the manufacturer. If Sparkfun's contract for the Fluke knock-offs didn't have such a clause, I'm sure their standard contract will in the future.

about a month ago
top

The Poor Neglected Gifted Child

dtmos Indeed. (529 comments)

I'm from the same era, and can corroborate nani's experience. Even the football players in my high school -- the guys with scratches on the back of their hands, from dragging them along the ground as they walked -- could name the planets in order.

Of course, since schools were funded by a property tax on the local landowners, the same opportunities were not available to the poorer kids going to the school on the other side of town. The desire was to raise that school to the academic level of the rich school, by spending more on education in general, but what seems to have happened is that the funding was just averaged between them, leading to the poor neglected gifted child syndrome.

about a month ago
top

NASA Forgets How To Talk To ICE/ISEE-3 Spacecraft

dtmos What, exactly, is missing? (166 comments)

Is it the entire 2 GHz transmitter that is missing? Just the power amplifier? Just the PCM modulator? The feed for the 70m dish?

What, exactly, is missing?

about a month and a half ago
top

Bugatti 100P Rebuilt: The Plane That Could've Turned the Battle of Britain

dtmos Re:What is "computer-directed flight control"? (353 comments)

they need High voltage AC to heat the plate.

Er, no. They need high voltage DC, not AC, to bias the plate, not heat it. The goal is to encourage electrons emitted from the heated cathode due to the Edison effect (thermionic emission) to travel to the plate, rather than stay in a cloud around the cathode as they would otherwise do. To do this, in typical operation the plate is biased positive with respect to the cathode. The plate only gets heated by the energy of the electrons striking it, an undesirable secondary effect.

about a month and a half ago
top

Live Q&A With Ex-TSA Agent Jason Harrington

dtmos Re:Unable to go through scanners (141 comments)

"You know, on second thought I think I'll take the bus."

You've apparently not heard of the TSA VIPR teams.

about a month and a half ago
top

Adjusting GPAs: A Statistician's Effort To Tackle Grade Inflation

dtmos Re:Grading by statistics (264 comments)

The IQR (inter-quartile range) would probably be a better measure of spread if you are going to use the median as a measure of center.

To be sure. The difficulty with IQR is that the average college sophomore has no idea what it is. I actually tried this one semester, and ended up having to teach statistics one-by-one to each student that came in complaining about his grade. It was easier, and took less of my time, to use a system that had less technical validity, but used terms with which the students were familiar, and could independently calculate.

I personally prefer that the median correspond to the center of the C range, rather than the top.

Consider it my small concession to grade inflation.

about 2 months ago
top

Adjusting GPAs: A Statistician's Effort To Tackle Grade Inflation

dtmos Re:Grading by statistics (264 comments)

Actually, no. Anyone that mastered the material did get an "A" -- that's part of the "law of large numbers." The medians (and means, and standard deviations) of the classes varied little.

about 2 months ago
top

Adjusting GPAs: A Statistician's Effort To Tackle Grade Inflation

dtmos Grading by statistics (264 comments)

When I taught undergraduate engineering courses at a state university, I always had large classes (> 80 students), so I decided to let the law of large numbers work to my advantage. I would grade each student's work with a numerical score, and would then find the median and standard deviation of the scores for each class. The median I defined to be the threshold between "C" and "B". One standard deviation above the median became the threshold between "B" and "A", and one standard deviation below the median became the threshold between "C" and "D". Any score below two standard deviations away from the median was a failing grade.

I used the median, instead of the mean, to ensure that I never had more than half the class with an "A" or "B". After some experimentation otherwise, it seemed like one standard deviation per grade was just about right -- most students got a "B" or "C", and only the exceptional ones got an "A" or "D" (or worse).

This scheme seemed to work well, and was no more arbitrary than any other. Plus, it was deterministic, in the sense that I could tell the students on Day One how I graded. If a student got a "C", for example, it was because more than half the class did better than he did. In addition, I could justify an "A" grade to the administration, since that person performed at least one standard deviation above the median.

about 2 months ago
top

Cygnus ISS Launch Delayed Due To Sun's Coronal Mass Ejection

dtmos Radioactivity? (30 comments)

Um, no. "Radiation" was the word for which you were looking. "Radioactivity" refers to the particles which are emitted from nuclei as a result of nuclear instability.

There was a significant solar flare at 1832z (1:32 p.m. EST) on 7 January, that bathed the Earth with electromagnetic radiation (X-rays, UV, radio, etc.). This was an X1.2-class flare, meaning that its flux would have peaked at 1.2E(-4) watts/square meter at the Earth's surface, had our atmosphere not protected those of us on the ground from the worst of its effects. The effects of the flare itself (largely attenuation of HF radio signals over the Western Hemisphere during and shortly after the event) are over and done with.

Since this flare was caused by a particular sun spot group that remains active and unstable, Orbital Sciences was concerned about a repeat performance when the Antares' avionics were in the upper atmosphere, and therefore not protected from a second, possibly even more intense, flare that the sun spot may produce.

Concurrent with this flare was a coronal mass ejection (CME), which consists largely of protons blasted out of the sun's atmosphere (the corona). Since these particles are protons, not massless photons, they travel slower than the speed of light, and it takes them a while to get here; they are expected to arrive sometime early on 9 January UTC. However, predictions of CME particle velocity are difficult and prone to error; CMEs can arrive early.

Since the CME could be arriving while the Antares was in operation (the flight was scheduled for liftoff at 1832z on 8 January), and the performance of the rocket's avionics could not be guaranteed in that environment, when this risk was combined with the risk of another X-class flare I think they just decided that a scrub was the wiser choice.

about 3 months ago
top

Feds Announce Test Sites For Drone Aircraft

dtmos Eh? (78 comments)

I thought we'd been testing them in other nations' skies for a while now -- what more needs to be done?

about 4 months ago
top

Atlanta Man Shatters Coast-to-Coast Driving Record, Averaging 98MPH

dtmos Whoosh! (666 comments)

I'm pretty sure this guy passes me every day on the way to the office.

about 5 months ago
top

20-Somethings Think It's OK To Text and Answer Calls In Business Meetings

dtmos Pfft. (453 comments)

Most 50- and 60-somethings I know think it's OK, too.

about 5 months ago
top

Georgia Cop Issues 800 Tickets To Drivers Texting At Red Lights

dtmos jerk yes, but VOIP? (1440 comments)

Hopefully this lets people know to put the damn phone away.

Well, actually, he's only ticketing people who use the phone to text, or send or receive Internet data traffic. Making phone calls? No problem.

I wonder what happens under Georgia law if one is making a cell phone call over VOIP, while stopped at a red light. Is that a voice call, or the use of Internet data?

Or what happens when one is on a conventional cell phone call, but has to enter additional data, like a password or to respond to an automatic answering system. Is that a move from voice to data?

about 7 months ago
top

Intel's Wine-Powered Microprocessor

dtmos Genevieve Bell? Mike Bell? (126 comments)

The engineer poured red wine into a glass containing circuitry on two metal boards during a keynote by Genevieve Bell, Intel fellow, at the Intel Developer Forum in San Francisco.

[. . .]

Low power doesn't mean low performance, with Intel now thinking about microwatts, not milliwatts, said Mike Bell, vice president and general manager of the New Devices group, during an appearance at the keynote.

[. . .]

Future computing devices will be able to understand human behavior through data gathered by embedded sensors and other wearable technology, Bell said. Projects are also underway at Intel labs to bring a more "human element" to mobility, she said.

What a poorly edited article. One never knows which Bell -- Genevieve or Mike -- is speaking.

about 7 months ago

Submissions

top

Amateur Radio Gets Secondary MF Allocation at WRC-12

dtmos dtmos writes  |  more than 2 years ago

dtmos (447842) writes "The ARRL is reporting that "delegates attending the 2012 World Radiocommunication Conference (WRC-12) in Geneva have approved a new 7-kilohertz-wide secondary allocation between 472-479 kHz for the Amateur Radio Service." This band, below the AM broadcast band, will retain its primary ship-to-shore and radionavigation beacon allocation. Due to the unique propagation characteristics of this part of the spectrum, an allocation has long been desired by the amateur radio community. Much as moonbounce and meteor scatter have produced their own amateur digital communication protocols (OSS under the Gnu GPL, of course), I expect the unique channel impairments of this band will lead to the development of dedicated digital communication schemes (beyond QRSS)."
top

Coronal Mass Ejection hits Earth

dtmos dtmos writes  |  more than 2 years ago

dtmos (447842) writes "Spaceweather reports "A coronal mass ejection (CME) hit Earth on Oct. 24th at approximately 1800 UT (2:00 pm EDT). The impact strongly compressed Earth's magnetic field, directly exposing geosynchronous satellites to solar wind plasma, and sparked an intense geomagnetic storm. As night fell over North America, auroras spilled across the Canadian border into the contiguous United States." Aurora were seen as far south as Baileyton, Alabama."
Link to Original Source
top

Sports Bars Changing Channels to Video Gamers

dtmos dtmos writes  |  more than 2 years ago

dtmos (447842) writes "This summer, 'Starcraft II' has become the newest barroom spectator sport. Fans organize so-called Barcraft events, taking over pubs and bistros from Honolulu to Florida and switching big-screen TV sets to Internet broadcasts of professional game matches.

As they root for their on-screen superstars, "Starcraft" enthusiasts can sow confusion among regular patrons ... But for sports-bar owners, "Starcraft" viewers represent a key new source of revenue from a demographic—self-described geeks—they hadn't attracted before."

Link to Original Source
top

DARPA Hypersonic Vehicle Splash Down Confirmed

dtmos dtmos writes  |  more than 2 years ago

dtmos (447842) writes "The U.S. Defense Advanced Research Projects Agency (DARPA) has announced that its Falcon Hypersonic Technology Vehicle 2 (HTV-2) flight on Thursday, 11 August, "experienced a flight anomaly post perigee and into the vehicle’s climb. The anomaly prompted the vehicle’s autonomous flight safety system to use the craft’s aerodynamic systems to make a controlled descent and splash down into the ocean."

“According to a preliminary review of the data collected prior to the anomaly encountered by the HTV-2 during its second test flight,” said DARPA Director Regina Dugan, “HTV-2 demonstrated stable aerodynamically controlled Mach 20 hypersonic flight for approximately three minutes. It appears that the engineering changes put into place following the vehicle’s first flight test in April 2010 were effective. We do not yet know the cause of the anomaly for Flight 2.”"

Link to Original Source
top

IEEEXtreme 24 Hour Programming Challenge Announced

dtmos dtmos writes  |  more than 3 years ago

dtmos (447842) writes "IEEEXtreme is a global challenge in which teams of student members, supported by an IEEE Student Branch, advised and proctored by an IEEE Member, compete in a 24-hour time span against each other to solve a set of programming problems. IEEEXtreme 4.0 will take place on Saturday 23 October, 2010. Not a student? The IEEE is looking for proctors."
Link to Original Source
top

Factorization of a 768-bit RSA modulus

dtmos dtmos writes  |  more than 4 years ago

dtmos (447842) writes "The 768-bit, 232-digit number RSA-768 has been factored. From the introduction:

The number RSA-768 was taken from the now obsolete RSA Challenge list as a representative 768-bit RSA modulus. This result is a record for factoring general integers. Factoring a 1024-bit RSA modulus would be about a thousand times harder, and a 768-bit RSA modulus is several thousands times harder to factor than a 512-bit one. Because the first factorization of a 512-bit RSA modulus was reported only a decade ago it is not unreasonable to expect that 1024-bit RSA moduli can be factored well within the next decade by an academic effort such as ours . . . . Thus, it would be prudent to phase out usage of 1024-bit RSA within the next three to four years.

"

Link to Original Source
top

USPTO Asking For Ideas to Enhance Patent Quality

dtmos dtmos writes  |  more than 4 years ago

dtmos (447842) writes "Tired of seeing poor-quality patents issue? Have a great way to solve the problem? Well, here's your chance to be part of the solution. The USPTO has issued a Request for Comments on Enhancement in the Quality of Patents [pdf], seeking public comment on ways to improve "the process for obtaining the best prior art, preparation of the initial application, and examination and prosecution of the application." Comments should be sent to patent_quality_comments@uspto.gov by February 8, 2010."
Link to Original Source

Journals

dtmos has no journal entries.

Slashdot Account

Need an Account?

Forgot your password?

Don't worry, we never post anything without your permission.

Submission Text Formatting Tips

We support a small subset of HTML, namely these tags:

  • b
  • i
  • p
  • br
  • a
  • ol
  • ul
  • li
  • dl
  • dt
  • dd
  • em
  • strong
  • tt
  • blockquote
  • div
  • quote
  • ecode

"ecode" can be used for code snippets, for example:

<ecode>    while(1) { do_something(); } </ecode>
Sign up for Slashdot Newsletters
Create a Slashdot Account

Loading...