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The One App You Need On Your Resume If You Want a Job At Google

joe_frisch Re:Octave (198 comments)

Why is matlab on a cluster stupid? It has some parallel tools that work well for certain types of jobs.

2 days ago
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The One App You Need On Your Resume If You Want a Job At Google

joe_frisch Re:Python (198 comments)

I use Matlab and Python at work. They are good for different things.
IMHO matlab has much more powerful graphics and debugging features. It is better set up for doing vector algebra problems. Python is better for some other forms of non-mathematical data operations. For most of my work Matlab is the better tool. On the windows platform it is much easier to install and manage .

We run the SLAC accelerators using both for analysis and non-realtime feedback, but Matlab is generally the preferred tool by most of the physicists.

Talking about which is better is like asking if a Semi-truck or a bus is a better vehicle. It all depends on what you are trying to move .

You can solve any problem in either of them (or in C, or fortran or COBOL if you really want), its just a case of which tool is better for the types of problems you are solving.

2 days ago
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FBI Director Continues His Campaign Against Encryption

joe_frisch I feel pretty safe (281 comments)

Seriously. By a large margin I am most likely to die due to an age related illness.Somewhere after that are non-age related illnesses. Then accidents.Then Suicide. Being killed by "bad people" is WAY down the list. Why on earth should I give up my rights to protect myself from a tiny chance of death?

Obviously people in power would like more control over me, but why should I agree to it?

4 days ago
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When will the first successful manned Mars mission happen?

joe_frisch We no longer do things because they are hard (217 comments)

We could go to mars. Build colonies, expand into the universe. It would be very hard and very expensive and take centuries, and all we would get in return would be... everything.

 

5 days ago
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Wind Power Is Cheaper Than Coal, Leaked Report Shows

joe_frisch Re:Diseconomies (608 comments)

Economics has the concept of "externalities" - basically effects of an activity that are not captured in its production costs. These can be negative (like pollution) or positive (like increasing productivity from a transit system).

One of the primary jobs of governments is to help correct the effects of externalities through regulation and taxes. The particular problem here is that the externalities (for CO2) are global, but the governments are local. This makes proper taxation / regulation difficult. If a government taxes industry to account for global pollution, but if other governments do not, that will tend to drive industry to non-regulated and likely dirtier locations (resulting in MORE pollution not less). It may be possible to fix this with import taxes on these goods, but that gets into the very difficult and political world of international trade regulations.

Not saying it can't be done, but its tricky.

about a week ago
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VeraCrypt Is the New TrueCrypt -- and It's Better

joe_frisch Re:Nope not suspicious at all (220 comments)

That is EXACTLY the problem. Determining a chain of trust is tricky. Producing a chain of trust that a non-expert can trust is almost impossible. Most users cannot verify the algorithms themselves so they have to rely on the evaluation of other people. But, how to trust those other people?

Government organizations have the resources to flood discussion groups like this with reasonable-sounding statements about how well something has been verified, while discrediting anyone who posts an message disagreeing.

If someone posts that I am wrong, how can I, or any non-expert know if the arguments against this post are valid?

about a week ago
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Independent Researchers Test Rossi's Alleged Cold Fusion Device For 32 Days

joe_frisch Re:Any suffiently advanced tech... (973 comments)

There are too many ways for this result to be wrong.

As many have pointed out an open-air calorimeter is the wrong way to measure heat. Any competent experimental scientist would know this. Its very easy to get this wrong by a big factor.

A very big problem is that the "dummy reactor" was operated at low power .(500W). since the thermal emisssion and convection are nonlinear, this is a very poor way to do a calibration. The excuse:

". In fact, it is well known that some Inconel cables have a crystalline structure that is modified by temperature, and are capable of withstanding high currents only if they are operated at the appropriate temperature"

Is VERY thin. If true it simply means that the dummy reactor is not an appropriate calibration. Again a competent experimental scientists would know this.

Then if it is intentional fraud, there are a LOT of ways to sneak power into the system. We are only talking a couple of KW of output - you can hide a wire carrying a couple of amps at a KV very easily. Also if there is a possibility of fraud you need to check EVERYTHING. Is the mains voltage what is claimed? Did the experimenters provide all of their own test equipment - thermal cameras, voltmeters etc. Is the lab locked and sealed from any possible entry? Are there hidden wires or fuel lines inside of the test apparatus?

The combination of poor experimental technique, lack of a physical model for fusion without radiation, and the huge financial motivation make it extremely unlikely that this is real. Whether it is outright fraud or misunderstanding is not clear.

about a week ago
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Facebook Apologizes To Drag Queens Over "Real Name" Rule

joe_frisch Re:Why only LGBT? (280 comments)

Could just be an oversight.
I support anyone's right to self identify gender, dress as they want,engage in consensual activities with anyone they want, If I'm missing something on this list I likely support that as well. But - I don't actually know the correct all-inclusive term to use and had though that LGBT covered everything.

about three weeks ago
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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 three weeks 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 2 months 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 2 months 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 2 months 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 2 months 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 3 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 3 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 3 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 3 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 3 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 3 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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