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Why India's Mars Probe Was So Cheap

joe_frisch Tricky to count costs in government projects (200 comments)

Its not easy to compare costs for projects done by different governments. There are different accounting standards for what is "in" and "out" of the project costs. I know nothing about the rules in India, but in Europe, scientific / engineering labor is not included in the "project". I expect the Indian probe was less expensive than a comparable NASA probe, but maybe not by nearly as large a margin as it seems.

This doesn't detract from the mission being a great success for India.

about a week ago
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New Nail Polish Alerts Wearers To Date Rape Drugs

joe_frisch Re:Seriously, we're not rapists.... (595 comments)

If this is expensive (and maybe it isn't) then the question is whether this is an efficient way to spend money to reduce rapes. Its possible that other approaches (better surveillance in bars for example) could be more cost effective.

Again, I'm not objecting to this, just saying that it needs to be compared to other approaches. If it is cheap then it is probably a good solution. Even if its expensive, I think it is good to have it available to women who want to purchase it.

No question that having people stop committing rape would be great. I just don't know how to make them stop except through very indirect methods (like this one).

about a month ago
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New Nail Polish Alerts Wearers To Date Rape Drugs

joe_frisch Re:Seriously, we're not rapists.... (595 comments)

I agree.
There is the possible issue that if these are expensive, then they might be oversold by fear-mongering. I do not know how common date-rape drugs are, or what this costs, so I have no opinion as to whether or not is is a reasonable (cost effective) precaution. It does seem good to have this available for women who want it.

The other possible downside is if there is a significant false-positive rate. This wouldn't lead to convictions, but could possibly destroy the reputation of innocent people. In an ideal world the drink would be sent to a lab to be tested, but most women would (reasonably) leave immediately if they thought their date tried to drug them, and would then warn everyone they knew about that person.

The second problem would be helped if the product came with a strong recommendation that the victim take a sample of the drink for real analysis any time there was a positive indication.

about a month ago
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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.

about a month and a half ago
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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.

about a month and a half ago
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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 2 months ago
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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 2 months ago
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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 2 months ago
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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 2 months ago
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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 2 months ago
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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 2 months ago
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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 2 months ago
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Netflix Reduces Physical-Disc Processing, Keeps Prices the Same

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

EXACTLY.
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 2 months ago
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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 2 months ago
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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 2 months ago
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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 2 months ago
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"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 2 months ago
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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 2 months ago

Submissions

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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."

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