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Comment: Re:It depends (Score 2) 473

by AlejoHausner (#49337977) Attached to: No, It's Not Always Quicker To Do Things In Memory
OK, so the authors are bad programmers and don't understand how string concatenation works. Strings are contiguous arrays, whereas disk files are made up of consecutive blocks, which are accessed through an index. If you want to append to a file, you may add a block, and modify the end of the index. But if you want to append to an array, you are forced to allocate a whole fresh array, because strings use fixed-size arrays.

On the other hand, Java StringBuffers have amortized O(1) append cost. A StringBuffers occasionally re-allocate themselves to larger pieces of memory, and the amortized cost of an append is O(1).

Comment: Re:Talk versus Action (Score 1) 187

by AlejoHausner (#49147161) Attached to: Facebook Puts Users On Suicide Watch

Your comments are very thoughtful, but I would quibble with you when you call depression a chronic condition. Of course this is the prevailing view, but it suggests that depression is a purely physical and biological, and devoid of meaning. Such a view is relatively recent, dating from the 1980s, when Prozac was being marketed, and Eli Lilly needed to create the opinion that there was a medical need for their new drug. The logic of the "chronic" view of depression is that you have an incurable physical illness, and hence must take a pill for a long time, hopefully for life.

I am tempted to rant about corruption in the pharmaceutical industry, but instead I want to suggest an alternative explanation for depression: when I get depressed, there is an actual unresolved conflict, one that I'm trying to put out of my mind. My mental energies become tied up in the large effort needed to forget my conflict, which causes pain every time it comes to my consciousness. The lack of energy leads to loss of motivation, and the world seems too much to handle. This forgetting is what psychodynamic therapies call repression. We tend to forget very easily; being present and remembering actually takes dedication. As Nietzsche said,

"I have done this," says my memory. "I cannot have done this," says my pride, and remains steadfast. Eventually, memory yields.

I would suggest that depressed people try to get hold of a good psychodynamic therapist, one who will not simply focus on symptom management, but rather someone who can go deeper into what's actually tormenting you.

Comment: Here is some actual information (Score 1) 55

by AlejoHausner (#49070075) Attached to: Drones and Satellites Spot Lost Civilizations In Unlikely Places
OK folks, let's stop griping about the OP and try to get some actual content. If you look at the home page of David Mattingly, the main researcher on this project, and check his list of publications, you'll hit this one:

It describes his team's exploration of previously-unknown settlement by Garamantes people, ancestors of today's Tuaregs, who dominated the Sahara from 500 BC to 700 AD. Cool stuff. He's been working in the area for 20 years, and the people in question were known to the classical Greeks and Romans.

Comment: Re:Fancy version of FTP (Score 2) 124

Touche'. Still, I'm amazed that there's a company called logmein that provides remote desktop service on the internet, and that (get this) it works by taking over the host computer's mouse and display! On X-windows (yes, I know) the computer you're logging into (the client) isn't affected visually; the displayed windows all exist as separate entities on the computer requesting the connection (ie the "display server"). Surely that makes a heck of a lot more sense.

Comment: Fancy version of FTP (Score 0) 124

You could also install an FTP server on one machine, and log into it from the other, type 'bin', and 'get'. Frankly, this particular feature has been available since the 1980s.

What will they think of next? Remote desktop? It was called X-windows in the 1980s.

Kids these days think they invented sex.

Comment: WRF has gotten pretty good, actually (Score 2) 77

by AlejoHausner (#48056529) Attached to: Supercomputing Upgrade Produces High-Resolution Storm Forecasts
I worked in meteorology in the 1980s for several years, and one thing I learned was that data is in short supply. I learned that the ultimate truth comes from sending up radiosonde balloons with humidity, wind and pressure sensors. The goal is not just to get data from the ground (there's lots of that kind of data, I'm sure). You have to sample the whole atmosphere to set up the numerical models. You say that about two hundred balloons are sent up every day, and assuming this is done every 6 hours in the continental USA, a back of the envelope calculation says the sample points are about 400 km apart. So the best data for seeding the calculations has very low spatial resolution, much lower than the 2-mile resolution used in the numerical model.

Of course, you can get estimates for water vapour from IR satellite measurements. I saw this done also in the 1980s. At the time I didn't understand all the math used to do this, but remember that it involved taking IR emissions over several wavelength bands, and somehow combining these to infer the water vapour content at various heights in the atmosphere, under each pixel. These satellites certainly have 2-mile spatial resolution, but the problem I see there is that the polar-orbiting satellites that provide this information pass over any spot on earth about 4 times per day, so the temporal resolution is as low as the balloons'.

Finally, data from airlines is going to be largely restricted to heights at cruising altitude, so you're missing a large cross section of the atmosphere there.

And don't get me started on weather observations over the ocean, where there are very few ground stations or balloons.

The issue is that the Navier- Stokes equations being solved in weather forecasting are very sensitive to initial conditions, so it's really crucial to get the data right to set up the calculations. Sitting in my armchair, I remain a bit skeptical that we will ever be able to get the true initial conditions.

Despite all this I'm always impressed that the NWS manages to get pretty decent one-week forecasts out, despite the impossible task they face. There must be some deep voodoo in those numerical models!

Comment: Teaching literature the old-fashioned way (Score 1) 89

by AlejoHausner (#47978619) Attached to: Ancient Campfires Led To the Rise of Storytelling
Some years ago my wife and I read Homer's Odyssey to each other over several nights, sitting outside next to a campfire. It really worked well. That's a story that is best told, not read. I wonder how much more effective it would be to cover ancient literature in this way: not read out of a book in classroom, but spoken out loud in a communal setting.

Comment: Re:It's not really a myth anymore (Score 1) 222

by AlejoHausner (#47185293) Attached to: The Sci-Fi Myth of Killer Machines
Your example of drones killing hapless Afghan and Yemeni wedding parties is a straw man. The author isn't talking about that. He's talking about INTENT. When you kill someone by means of a drone, you are merely extending the operator's range of action. The drone is just an extension of the operator's hands. It's like driving a car. The driver has all the intent, and the car merely amplifies it. You might put the car on cruise control, but a car on cruise control doesn't plan its next move.

I think it's impossible to simulate intention. People mistake intention with mathematical knowledge. That's why the term "artificial intelligence" is so wrong and so limited. Consciousness and intention are much richer than mathematical intelligence. Consciousness and awareness require subtle skills that we humans use to interact with the real world; skills that are so subtle we barely notice ourselves using them. We certainly don't understand those skills. And since we don't understand them we can't build them into a computer program.

Writing software that interacts with the real world is very hard, because the world is too complicated and variable. Have you ever tried to write code that handles a user interface? It's very hard, because users are so varied in their assumptions about what your program is doing. Hell, you don't have to be a programmer to know that: we have all run into bad UIs. That's why the iPhone was such a big hit: its designers paid a huge amount of effort and time to make sure the UI worked well. Previous phones had UIs written by the phone's engineers as an afterthought. Those UIs sucked, and the iPhone ate their lunch.

Even though writing a UI is so hard, users have to learn how to use it. They have to get accustomed to its limitations. A general purpose UI that could interact with the untamed world is probably impossible to write. So much more impossible must it be to write a program that can interact with the real world and plan that world's destruction.

Comment: In 1980 we had video terminals! (Score 1) 230

by AlejoHausner (#46884435) Attached to: One-a-Day-Compiles: Good Enough For Government Work In 1983
In high school in Toronto in 1978, we would hand-code our Fortran programs onto optical cards by strategically darkening in circles with pencil, to encode one line of source per card. The teacher would then stack your cards onto a reader, which would scan one card a time (about one or two per minute) and a magical thing called a "modem" would send the program to the University of Toronto mainframe, which would compile and (if you were lucky) run it. The teacher picked up the printouts in the morning on the way to school. Truly an exciting time, but I only saw other lucky students use it; I never got a chance to try.

Then I had a transformative experience through a one-week stay at the University of Waterloo, where we spent all our time in front of teletypes programming in APL. Boy those teletypes were noisy, especially with a room with twenty of them going at it full blast. When I went to bed my ears would still be ringing. Yes, APL was my first programming language, and frankly the trauma hasn't worn off yet.

When I started university in 1980 at McGill in Montreal, there still were punch card machines and punch card readers at the computer center, and its satellite centers. However, pretty much everyone at the school had a "computer code", ie an account on the time sharing system called MUSIC: see wikipedia. It was a lovely system, and you could run commands interactively. It came with Fortran, Snobol, Pascal, Lisp, IBM 360 assembler, and, of course Adventure!

I spent many hours playing Adventure, and of course mapped the whole cave in detail.

At McGill, there were two kinds of terminals: video terminals for the lucky people, and paper terminals from Digital Equipment called DecWriters for everyone else. The former had wisiwig code editors, on which you could prepare your source code and, when ready, "submit" your program to be compiled, run and printed. You would then walk down to the basement of Burnside Hall, where a surly operator would hand you your printout. That's when you learned that you had a typo in your code. Needless to say we were told over and over to WRITE YOUR PROGRAMS OUT before you typed them in, but nobody listened then, and nobody listens now either. In any case, the turn-around time from "submit" to picking out your printout was in the order of 15 minutes, not overnight as in TFA.

The design of Watfiv fortran focused on fast compilation. Your code wouldn't be optimized, but that was OK, because as a student the majority of your runs would have compilation errors. Typically you only ran your program, fully implemented, once or twice, after dozens of botched compile runs.

All in all, it was a great experience. What I appreciate the most, in retrospect, was that CS students were required to learn IBM assembler. Higher level languages don't fully make sense until you know what's going on at the CPU level. I still can't fathom how an intro course in Java can give you any true knowledge of how computers work.

Comment: SSRI withdrawal (Score 1) 329

We won't know the exact position of the British Psychological Association until Monday, but I can offer one example of how a psychiatric diagnosis can cause harm. Look up "SSRI withdrawal". SSRIs like Prozac slow down the reabsorption of serotonin, leaving more serotonin available in the brain. The body isn't static, and it reacts to the drug by overstimulating serotonin absorption. The body and the drug eventually reach a balance, and the overall amount of serotonin returns to the original levels. The problem occurs when SSRIs are stopped abruptly. The body's compensation mechanism continues for a while, and your serotonin levels drop dramatically. You get VERY depressed. You may feel like killing yourself. Some people do commit suicide at this point. Seen from the outside, it looks like you were very ill, and stopping the drug unmasked the illness. But the opposite is true. Stopping the drug CAUSED the illness. In fact, studies have shown that depressed people's serotonin levels are no different from those of normal people. Taking SSRIs doesn't change your levels because your body compensates and returns your serotonin to pre- treatment levels. The SSRIs don't do anything. Except that if you stop taking them you might die. Better off not taking them. And better off not being diagnosed in the first place. Diagnosis can kill.

Comment: Oil and coal are here to stay (Score 2) 262

Sadly, there are lots of reasons why renewable sources won't solve our energy needs. Tom Murphy, a physics prof at UCSD, has a great blog where he works out the details. This was covered a while ago here:

Comment: Re:World of Goo (Score 1) 279

by AlejoHausner (#42892803) Attached to: Ask Slashdot: Really Short Time Wasters?
Awesome puzzle collection. I am also currently hooked on signpost, but I still like pattern, netgame, loopy, galaxies, dominosa, and magnets. All are highly configurable to suit your time-wasting budget. Classic puzzles like mastermind, sudoku (regular, jigsaw, killer), minesweeper, black box, and kenken are there too! The iOS port does suck, but hey Simon's puzzles are open source, so you could port them yourself. Android, Mac, and Windows ports are all well done. I even use it on my old Palm device! Yay open source!

To communicate is the beginning of understanding. -- AT&T