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!



Where are the Flying Cars? (Video; Part Two of Two)

joe_frisch Re:Two categories of future tech (66 comments)

Have we really surpassed SiFi expectations? We don't have humanoid robots, intelligent computers, or unlimited longevity. We haven't cured cancer. Our computers have lots of "flops" and "gigabytes" but they don't do nearly as much as was expected in the 50s. We have moderately stronger materials, but nothing really amazing compared to 50's tech. (Ultra-strong metallic whiskers have been known for a long time). We don't have 3-d projectors in common use, and we can't 3d print our food. (mostly)

Communication is better than I think most people expected and the ubiquitousness of the internet is well beyond what was imagined.

What have we done that is so amazing - to a 1950s audience that is.

Of course science fiction is not really a good guide to the future, the writers are often not experts at what is technologically possible.

5 days ago

World's Fastest Camera Captures 4.4 Trillion Frames Per Second

joe_frisch Re:Things that go fast (94 comments)

Most particle physics happens on much faster time scales than picoseconds. There is some slower physics but that can generally be measured by looking at the verticies where tracks diverge and calculating the time it too particles to get to those vertices.

For measuring beams rather than the individual particle collisions we can use transverse deflection structures (a sort of streak-camera on steroids) to get to resolutions of a few femtoseconds.

The original article is a nice technique, but whether it is the fastest depends on how you define "camera". It is probably the fastest for 2-d images, but there are much faster 1-d imagers.

5 days ago

NASA Tests Microwave Space Drive

joe_frisch Re:Ugh (201 comments)

The test was done in air. There are a huge number of possible sources for thrust. Most notable are convection currents from temperature differences. Even if the test is done in vacuum, you need to be very careful. Temperature changes can cause out-gassing. Thermal radiation will generate force from photon pressure.

Newtonian physics was (and still is) extremely accurate in the range in which it was tested. The flaws were found under new conditions (relatively strong fields and fast motions of planets, and detailed measurements of the speed of light).

The amount of physics knowledge now is vastly greater than it was in 1900. My day job involves working with electrons at .99999999C. As I sit here I am looking at the energy of X-rays generated from scattering off of 12 GeV electrons - getting the correct energy relies on conservation of mass energy. Conservation of mass-energy is measured in everything from planetary orbits, to electron diffraction, to neutron star binaries, to high energy collisions.

This device is not operating in any new physical regime. The energies and length scales are quite modest.There is no physical explanation of what is going on (quantum mechanics conserves mass-energy). Its a very dirty experiment (done in air etc), so it is enormously more likely to be a mistake than the discovery of a new physical principal.

about two weeks ago

Google Spots Explicit Images of a Child In Man's Email, Tips Off Police

joe_frisch Re:compared to hash database, with antivirus (790 comments)

Certainly anyone who emails child porn is stupid.

So if there is a child-porn detection tool, is it available to the public to automatically block an illegal images from web sites and email? I don't know if the database is just things that are obviously child porn, or includes nude pictures that are not obviously underage.

I'm not sure of the legal implications of a botnet spamming millions of people with illegal images. Most users do no know how to erase all of the copies from cache.

about two weeks ago

Google Spots Explicit Images of a Child In Man's Email, Tips Off Police

joe_frisch Re:compared to hash database, with antivirus (790 comments)

Which seems like a great way to catch the minor offenders who are trading old pictures, but not the really serious offenders who are producing NEW child porn. One could even argue that it creates a market for new child porn that doesn't have known signatures.

I wonder if child porn is the only type of material that is checked against a known database?

about two weeks ago

NASA Tests Microwave Space Drive

joe_frisch Re:Always left out... (201 comments)

People often miss that the problem with ion drives and other electrical drives is that the exhaust velocity is too HIGH, not too low.

The higher the exhaust velocity, the more power you need for the same thrust. Making high specific impulse drives is easy - a microwave source can be ~80% efficient and has an exhaust velocity of the speed of light. The problem is that the power requirements are enormous.

Sure, energy from the sun is "free", but the mass of the solar cells to collect that energy is not free. With a speed-of-light drive the thrust to weight ration is exceedingly small for conventional power sources (which includes nuclear and solar) so the acceleration is too small to be useful for most applications.

If you imagine a solar powered spacecraft, you need to be sure that over the lifetime of the mission you would get more total velocity change out of the solar cells and electrical drive than you would from the same weight of chemical rockets. For ion drives and long missions this is true, but for a photon drive (or any other propellant-free drive it is not true for any reasonable length mission).

about three weeks ago

NASA Tests Microwave Space Drive

joe_frisch Re:Ugh (201 comments)

Some NASA employees are experts, but that doesn't mean that all NASA employees are experts.

If the thrust is only proportional to the photon pressure from microwaves, then this is not particularly interesting.

If the thrust is from somehow accelerating ions, electrons, or ambient air molecules, this is not particularly interesting. (just a different type of ion drive)

If there is thrust with no exhaust, if it doesn't conserve momentum, then the device is impossible.
Yes, IMPOSSIBLE. Conservation of 4-momentum is among the best tested bits of physics. "quantum mumble" doesn't change that - quantum mechanics also conserves momentum.

about three weeks ago

OKCupid Experiments on Users Too

joe_frisch Re:Ok Cupid.... (161 comments)

The particularly stupid part was messing with their match algorithm. If they imply that their algorithm has any value, then their users will feel at least ripped off (since the algorithm doesn't seem to work well), and possibly angry because they were given incorrect information .

Blocking pictures was visible to users and I don't have any problem with that .

about three weeks ago

China Plans Particle Colliders That Would Dwarf CERN's LHC

joe_frisch Re:Suboptimal Design (219 comments)

There are a variety of tradeoffs between circular and linear electron / positron machines. At very high energies (>~500GeV CM) the circular machines become impractical At low energies (100 GeV CM) a circular machine is considerably simpler and cheaper. Inbetween the trade-offs are not completely obvious.

about a month ago

Netflix Reduces Physical-Disc Processing, Keeps Prices the Same

joe_frisch Re:Why do you want pieces of plastic (354 comments)

I would much prefer streaming if the same content were available but it isn't. In particular many recent releases are only available in physical disks. If netflix wants to go to an all streaming model it needs to talk to its suppliers, not its customers .

about a month ago

A Look At NASA's Orion Project

joe_frisch Re:That's not an Orion... (108 comments)

Mod parent +1 awesome.

I'm particularly amused that people seriously considered nuclear bomb pulse propulsion for EARTH TAKEOFF. And to think modern wimps complain about airport noise.....

about a month ago

Apollo 11 Moon Landing Turns 45

joe_frisch Re:US, the moon. China, mars. (211 comments)

US may be more like Byzantium, a slow centuries-long decline. Reliving its past glories "safe" behind its invulnerable walls.

Civilizations rise and fall. Its not clear who's next. China is making rapid progress, but it isn't clear if they will regain their millennia long place as world leaders, or crash and burn on the next economic downturn. I hope they make it though - I'd rather it were us, but I want someone in space.

about a month ago

Apollo 11 Moon Landing Turns 45

joe_frisch Re:The biggest problem with the space shuttle (211 comments)

While I agree with this, I think there is also the issue that the shuttle was not a very good general purpose launch vehicle - or more correctly general purpose launch vehicles do not seem like a good engineering solution.

For missions where you need to send men and equipment into orbit and bring them down again the Shuttle is fine. If you just want to put cargo into orbit, the extra weight and complexity is not worth it. If you just want to put men in orbit and return them, then a smaller vehicle works.

The design of launch vehicles is so marginal that it is not worth providing for a lot of mission flexibility. The early shuttle concepts recognized this and had non-returning heavy-lift variants.

about a month ago

"Intelligent" Avatars Poised To Manage Airline Check-In

joe_frisch First - why do we need checkin (102 comments)

I check in online. When I get to the airport, why can't I just swipe my passport drop my bags on the conveyor and go on my way. Sometimes that works, but at least half the time while someone types the Oxford English Dictionary into a keyboard. I'm not changing flights. I'm doing exactly what my reservation, and online checkin said I was doing.

I don't want a human touch, I just want to get on my airplane.

On the occasions where I am doing something unusual, or where something goes wrong, an AI avatar is NOT going to be able to solve my problem.

about a month ago

The debate over climate change is..

joe_frisch Re:n/t (278 comments)

There is lots of good, extremely complex science being done. What you see in the media though is almost entirely idiots yelling about politics.

about a month ago

Airbus Patents Windowless Cockpit That Would Increase Pilots' Field of View

joe_frisch Re:And when the video feed dies... (468 comments)

Assuming CATIIIc zero visibility operations will be approved, a lack of windows should be fine for normal taxi and flight. The pilots are already relying on operating entirely by instruments.

That said, there could be emergencies where real outside visibility would be nice - water ditching, etc. Those may be rare enough though that it isn't a significant extra risk.

Will sure may flying airliners even less interesting than it is now.

about a month and a half ago
top, Mensa Create Dating Site For Geniuses

joe_frisch Re:IF.. (561 comments)

I think part of the problem is that what we think of as "intelligence" is a vector quantity and can't be well described by a scalar like IQ. You can define some metric on the vector intelligence, but that metric will be arbitrary. You can think of "intelligence" as a combination of memory, quick-thinking, spatial visualization, abstract mathematical ability, social abilities, etc etc. What combination of those are important will be different depending on what activity you are doing.

The particular problem here is that most people want intelligent companions in order to have interesting conversations. I don't think the standard IQ measurement is a good indicator of how interesting someone is to talk to.

I think most people just naturally find others with compatible ways of thinking. So using IQ to find companions who are also looking for high IQs may be pre-selecting for people who are not very good at socializing. Its not that high IQ makes you bad at socializing, but rather that if you are good at socializing, you won't need to use IQ to pre-select.

about 2 months ago

Court Releases DOJ Memo Justifying Drone Strike On US Citizen

joe_frisch Re:Military use of force (371 comments)

The lack of a formal declaration of war is one problem. The other is the idea of a "global" war on terrorism. In a conventional war, someone operating within an enemy country can be considered an enemy and is reasonable target for an attack. The geographic limits on targets put a limit on the ability of the US to simply execute citizens. An American citizen in an enemy country is a legitimate target of attack in the same way that (with some restrictions) anything else in that country is a valid target. However, military attacks when there is not a state of war with a country are normally not considered legal.

With this "global" war on terrorists, we are essentially saying that we can declare anyone anywhere to be an enemy, and then kill them. By this logic could China use a drone to kill an Chinese citizen in the US if they believe he holds a high position in Falun Gong? Could this argument be used to execute rather than arrest a US citizen IN the US if his capture was believed to be too dangerous?

It seems to be a dangerous blurring of the line between law enforcement and war.

about 2 months ago

Court Releases DOJ Memo Justifying Drone Strike On US Citizen

joe_frisch Re:Military justification (371 comments)

But all of this information comes from the same government that executed him. Its very likely he was involved, but did his involvement rise to the level of a capital crime? Is there even a death sentence for conspiracy to commit murder?

about 2 months ago



Ask Slashdot: Computers for the elderly

joe_frisch joe_frisch writes  |  more than 2 years ago

joe_frisch (1366229) writes "There is a growing group of elderly computer users who have learned to be productive with a particular interface, say windows XP and office 2003, and who do not have the interest or energy to learn something new like Windows 7 or the office "ribbon". They continue to use aging and unreliable computers because they do not know how to order new computers with the older interface. Many of these users are relatively wealthy so this is potentially a valuable market.

While it it possible to cobble something together, with time it becomes increasingly difficult, especially for the often minimally computer-literate people in this market. In addition, as older software is no longer supported it will be increasingly susceptible to viruses. What would be ideal is a old style interface to updated programs and operating systems.

What are the options — and remember the target market is NOT people who read slashdot, suggesting that they use Debian is not going to work."


joe_frisch has no journal entries.

Slashdot Login

Need an Account?

Forgot your password?

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>