Whether Linux is appropriate depends largely on the type of project you're doing. You're probably aware that tons of routers and assorted network gear runs Linux. It might be the best choice if that's what you're doing. But if you're trying to do hard realtime control with Linux... well, if your experience is anything like mine was, it'll be painful.
I did a project with a 266 MHz PII single-board computer once. I chose it because it had tons of on-board A/D and D/A, and when I ordered it I asked the company for their Linux drivers, etc, as well (which they advertised). They sent me a customized version of Redhat to be installed on the development machine, and a bunch of tools to set up a stripped down distro on the target as well, using the same libc libraries, etc.
There were numerous errors in what they sent me, including stupid things like configuration files having DOS instead of UNIX line endings. How this got out the door I do not know. But, I could fix all those dumb oversights, so that wasn't the problem.
The issue was that the distro they sent did not include any realtime extensions (a must for my application), so I endeavored to install RTAI on it. This was where I began to have real problems.
The kernel they were using was old -- 2.2.some-low-number. Assuming this is what their drivers would work with, I found the vanilla source from kernel.org for a nearby 2.2 version, slightly higher, compiled it, no problems. I then tried it with their extra A/D and D/A drivers compiled in: no problems. Then, I tried it with the RTAI extensions (without their extra drivers: Test one thing at a time!) It compiled, but when I tried to run RTAI diagnostic programs the machine would unceremoniously reboot. No good.
"Ok," I thought, "this is a pretty old version of RTAI. Let's try a newer version; maybe that's a little more mature." In order to do that, I needed to use either a 2.4 or a 2.6 kernel. So, I started by trying to build a 2.4 or a 2.6 kernel, again from kernel.org, first, without either RTAI or the extra drivers. First problem: gcc too old. Solution: Compiled on another machine (really, coLinux on my laptop, running Debian Sarge). But after putting the kernel images in the correct locations and reinstalling the boatloader with lilo as you'd expect, the machine would just reboot every time it'd start to execute the kernel. This happened for more permutations than I can remember of 2.4 and 2.6 kernel versions, and configuration options.
Unable to get RTAI working on an old kernel, and unable to get a new kernel to run, (and desperately needing realtime), I ended up putting DOS on the thing and writing code in 16-bit real mode. This gave me essentially unfettered access to the hardware, with fast interrupts, so that, even though people tend not to consider DOS an 'RTOS' per-se, it stayed out of my way enough that I was able to access the hardware directly and run with guaranteeable latencies.
DOS made lots of things harder -- networking and accessing extended memory in particular -- but solving each of those problems proved possible, since I was working with small enough atomic "pieces of the system" that they could be debugged. When I'd been trying to put together linux with RTAI with the given drivers, I was working with a big-monolithic-kernel... running-in-another-mini-kernel, and I could do little more than follow instructions, compile, and pray. If it'd worked, it'd've made my life much easier, but, when it didn't work, I was pretty much at a loss.
If you're on a tight time budget and you've never used embedded Linux before, as much as I love Linux, I've got to say: If you're doing a realtime project, just pay the money for a "real" RTOS.
** If anyone else has had different experiences, I'd be curious to hear them. Though it's too late now, I'd also be curious if anyone has some after-the-fact ideas about why the 2.4 and 2.6 kernels wouldn't execute.
You don't have any of these "rights" you speak of except in your imagination.
We have rights because we say we do.
From where else can rights come? Natural Law? Please! Not even life itself is a "natural" right: Murder is quite "natural," and it has been the common practice of man to conquer and kill, to rape and pillage, for most of recorded history (and certainly for what came before that too).
It is as we became more civilized that we gave those things up. We, generally, decided those things were wrong. Most of us homo sapiens decided life was a basic right of people. Some of us decided speech was too (but not all of us, for sure); some chose "religion" as well. There's some variety. And in each case, the key is this: We decided.
We humans create the world we inhabit for ourselves. Chalk it up to our opposable thumbs. And the world we inhabit, thanks to our largish frontal cortex, is not just a world of physical stuff, but of ideas, abstractions. The idea of "rights" is an abstraction we built. And we can do whatever we want with it.
So, what do you think your rights should be?
I think that one of mine -- a lesser one, for sure, but still something I'd like -- should be that I can move data around how I want. Not a big deal, and also, I think, not too much to ask. Whether they understand it or not, I'm not in the studios' way. I think they should stay out of mine.
Pffft. When I was a teenager, I always did it on my own. There never were any competitions that I knew of. Wait, what were we talking about again???
Back in the day, I remember there was a kid, two years younger than I was, in high school band, who "won" such a competition, and became famous for it. Y'see, it was a race. Ever since then, people called him "two stroke." And no, it wasn't an engine reference.
Perhaps the technique is standard frequency mixing [wikipedia.org], a standard technique used in practically every radio receiver these days.
Aye, the heterodyne radio receiver. Yeah, I could see them using a mixer! That doesn't mesh with what's described, but, then, (unless I am missing something), what's described doesn't make a ton of sense:
From TFA:
The researchers first generated a voltage-controlled CMOS oscillator, or CMOS VCO, operating at a fundamental frequency of 81GHz with phase-shifted outputs at 0, 90, 180 and 270
degrees, respectively. By linearly superimposing these four (or quadruple) rectified phase-shifted outputs in real time, they ultimately generated a waveform with a resultant oscillation frequency that is four times the fundamental frequency, or 324 GHz.
How can any linear system create an output frequency unequal to one of the input frequencies? I could see rectification as providing a frequency doubling -- but that's old, old news, generates horrid output, and is probably not what's referenced here.
So maybe the article gets it wrong, and you're right?
If somebody else could shed some light on this, that'd be cool.
There's actually no indication of feedback at all here (which is the whole point of a PLL). In general, actually, feedback slows systems down. They do mention that they are using a VCO -- also used in PLLs -- but I get the impression that the purpose here is to, say, generate frequency modulated radio signals; such a modulator would be an open-loop system.
And if it's a truly exceptional girl, the kind who's really your type, she might appreciate one of these:
"Baby, can I be your DNA helicase? 'Cause I want to unzip your genes."
"I wish I were your derivative, so I could lie tangent to your curves."
"If you're sine squared, I want to be cosine squared -- so that together we can be one."
Or, after you've known her for a bit, you could just say something sweet like, "Life without you is like a vector space in which the Cauchy sequence does not converge."
You catch her eye across the room. With a sly grin, you motion for her to walk over to you. It's a simple "I want you over here" hand gesture not unlike -- for a point of reference -- that used by Morpheus in The Matrix duing that famous fight scene.
She crosses the room; now she's standing close to you. "If I could make you come with my finger," you say, "Just imagine what I can do with my whole hand?"
>Yes but most homes in even moderately cold climates will use much more energy for heating than they can get from the sun and thus it will be cheaper to use the solar energy from the sun for heating and then grab the electricity you need of the grid ( which may very well come from super efficient solar collectors).
When you tell students not to cite Wikipedia, you're telling them to omit a citation for one of their sources. This is bad.
I use Wikipedia all the time, and I cite it, with no ill affects -- at the university level. That's because I use it correctly. Surely, if it's good enough for my engineering department, it's good enough for 10th graders?
Wikipedia is an amazing reference for basic applied math and computer science, and you can pry it from my cold, dead fingers.
In fact, come to think of it, every time I've cited Wikipedia in a paper, I've gotten an A on it. Better, for some of those papers I've received "course citations" -- special notes of positive recognition which are recorded on my transcript. One other professor made a point of stopping me and saying, "This is really a very good paper. Could you make an extra copy of it for me?" I call that success, n'est-ce pas?
I don't just cite Wikipedia, of course. I cite academic papers too. But those papers often don't spell out the basics -- so as an undergrad trying to apply more advanced math, I need some background, and Wikipedia provides that. (Textbooks would too, but it's quicker to go to the Wikipedia article -- and the Wikipedia article is often just as useful if not more). So in the spirit of full disclosure (and the Academic Honor Code), I cite all my sources. That means that, if I need to figure out how the Quaternions work and Wikipedia tells me, I cite Wikipedia.
Admittedly, I'm not researching history or some politically-loaded subject. I'm researching something which benefits from Wikipedia's huge nerd bias. Wikipedia is much more than an encyclopedia: Will I find a complete description of the quaternions in the Encyclopedia Brittanica? What about particle filters? How about the naive Bayes classifier or the ensemble Kalman filter? Wikipedia has those articles! If I go to the article titled State space (controls), Wikipedia goes so far as to show the nonlinear state-space model for a pendulum. I am sure Brittanica doesn't give that.
Librarians keep insisting that people use the Internet as we used Old Media. But it just doesn't work the same. What if some guy on the gamedev.net forum helps me out by sharing an idea with me; should I not cite him? I make a point of including proper footnotes, even for sources like that. Then, it's up to me to make that source authoritative -- by doing a correctness proof in the paper, for example. It takes a little legwork -- but if you immediately write off sources of information like that, you ignore most of the power of the Internet that Old Media lacked. Random, unpublished people know a lot of stuff. You need to verify it often, but it's still useful (and "verification" doesn't necessarily mean "appealing to authority"). As many posters have said, it sometimes just takes critical thinking.
>it will be more economical to use some black paint and water-filled pipes to heat your house than to use photovoltaic cells.
Definitely yes for heating. No, for electricity (at least in principle): Sunlight has a lot of exergy that you waste if you run it through a heat engine on Earth: You're limited by the temperature you can get your hot reservoir. This imposes some fundamental thermodynamic limits:
Via heat engine on earth
Say you use sunlight to heat your 'hot' reservoir to an exceedingly hot temperature. In solar power towers, liquid salt is used, which had a melting point of 1074K -- let's say you get your hot temperature there. Then, say you exhaust heat at room temperature: 22C = 295K. This gives you a Carnot efficiency of deltaT/Th=(1074-295)/1074=73%.
Direct from sun
Solar panels receive radiation from the sun, which is (nearly) a blackbody at 5762K. Again assuming the Earth where you're working is 22C, then you get a Carnot limit of (5762-295)/5762=95%.
So: This doesn't consider the practical efficiencies currently achieved by different technologies, nor the comparative economic efficiencies. But it does show that sunlight has an awful lot of exergy that you throw away by using basically any reasonable heat engine on Earth, and some sort of direct radiation-capturing technology (solar panels, etc) has the potential to be much more efficient.
When they put it all on one chip, they call it a Microcontroller. When they build it from a few chips, all soldered on a single board, it's called a Single Board Computer. So, this idea is quite widely baked.
>"Girls on the plus side[:] you can walk all over them and get anything you want."
(punctuation added)
I actually know a guy who does this. He dates pudgy girls who know damn well he could do better -- so they let him get away with murder. It's kind of sick, actually. He gets off on power and treats them like crap.
...because the post is interesting and insightful, and appears to be from someone qualified to say something which is (1) meaningful and (2) different from what everyone else is saying.
It's funny. I only have mod points when I don't want them.
This is among the most horrible things I have ever seen.
This is barbarism embraced as heritage.
Racism? This isn't about race. It's about (fucked-up) culture. Much (most?) barbarism happens outside the lines permitted by cultures: There are Americans who torture animals too -- but they are jailed if caught; the culture does not permit it. The problem is when culture encourages this stuff. Bullfighting, in Spain and Mexico, is another example; there is no good excuse for it.
In each case, it is "ethnic identity" which is the excuse used -- a concept which is hugely conflated with "race," but not the same (and that's important). The whole process by which ethnic identity works relies on othering -- defining who is outside the tribe. And race is great for that: it's pretty obvious most of the time. But it's just one way of achieving the more-general goal of defining a them.
So, to justify their dolphin-killing, I am sure that these "fishermen" call it their "heritage:" this is part of ethnic identity, and so relies on defining a them. "What, do you want to not kill dolphins," runs a dialogue which is neither spoken nor even explicitly thought through, "and be like one of those others?" You can insert the name of any derided out-group (local or global) for "others" before: Say, "Koreans," or, "white people."
Now here's the problem with what you said: When you made killing dolphins about race, you used the same kind of "othering" process that those killing them use as their justification. It's tempting, I know [fuck have I had some race issues in my life (interracial dating: didn't think it would be a big deal -- it was)]. But it's the wrong route, because as a side-effect it creates the same us and them categories that provide justification for horrors like this.
There's a huge area within which everything is relative. But outside that, there still exist objective right and wrong. And outside the relative zone, "ethnic identity" creates evil. I don't care if your grandfather did it: Think for yourself.
First, thanks to you and Cthefuture for pointing these out.
The only OSS shooters I was aware of were Cube and its sequel Sauerbraten. Those two are interesting in that they achieve quite a lot with, technically, very little -- the spatial heirarchies they use are quite primitive, and they don't do any occlusion culling, for starters. Cube, the simpler of the two, is actually pretty cool in that it will run, and run well, on damn near anything with a graphics card. Yet it somehow feels like little more than Doom.
So I just tried Warsow and Nexuiz.
Nexuiz: It could be that this game looks great on a monster gaming rig, but me, all I've got is a 3.5-year-old Dell laptop. 2 GHz Pentium M, Geforce somethingsomething mobile (the product numbers in this industry long ago stopped meaning anything: It supports the first version of vertex shaders, and no pixel shaders. UT2004 looks pretty good, and that's about my top end). And on my laptop, Nexuiz was less-than-impressive. In terms of eyecandy-per-dollar-of-computing-hardware, I was underwhelmed. I also agree with Cthefuture that it felt like Quake2.
I was much more impressed by Warsow! It put out nice graphics at a good framerate. It felt a lot like Quake III, with many hints of UT -- but hey, I liked both of those games. Compared to Nexuiz, the "effects" weren't as great, but the quality of artwork was superior: Professional, consistent, and appealing -- and the levels looked better. Unfortunately, there was nobody online to try playing against.
While I'm talking about OSS games -- and I know I'm veering dangerously near the realm of completely off-topic; forgive me, it's cool -- I'd also endorse TASpring. It's a strategy game, not a shooter, and it is also unapologetically a remake of the commercial Total Annihilation -- but it's quite good. Unfortunately, single-player (and the interface for it) is largely neglected, and AI, last I checked, was horrendous. But the multiplayer experience, the graphics, and of course the gameplay (I know: the part they ripped off), are all quite good.
If anyone else knows of any OSS games of Warsow caliber, I'd be curious to see them, whatever the genre.
>In terms of accuracy and surface finish RP models will not be able to match the smooth accurate even surfaces of molded parts, as RP models are created in discrete layers, layer by layer. Until those layers could be brought down extremely small (meaning enormously increasing processing times), the surface finish will always be "rough".
You can imagine schemes besides simple grids which could be faster with some sort of multi-resolution machine. With different-size pixels, you could imagine doing something like the Marching Cubes algorithm, instead of naive rasterization.
Of course, I understand that the layer-based machines couldn't implement that algorithm.
I also wonder if RP is really the right way to go about bringing production into the home. Something more like CNC would be more useful; then it's merely an issue of automation.
>you can't really believe that all universities are intending to pump you full of knowledge. That is not the purpose of their business, or how they get funding. Even tuition is just a minor part of the overall funding picture for most universities.
Universities? No. They're cold soulless businesses. But most of the professors I've had have seemed to care quite a bit about their teaching -- though I freely admit that my experience is probably not typical: My university has a highly-ranked undergraduate program, but pretty crappy graduate studies, which explains a lot about which professors then choose to take positions there.
>Yes, you as an individual can work hard, try to pass courses, and try to earn your degree.
Basically what I was saying is that "passing your courses" doesn't take "working hard." Getting As might, but simply passing, at least where I am, doesn't look that hard to do. You know, maybe the reason I don't worry is because of grade inflation! It's this experience that leads me to say, "Even if universities aren't primarily out to teach you, it is a good idea to try to learn as much as you can from them. The grades don't get hugely in the way."
>While it is a good idea to try and pick up some knowledge while you are going through the meat grinder of a college education, you should keep foremost that the knowledge is not the point. The real point is to "punch the ticket"
Where the hell did you go to school? I'm sorry. It sounds like it really sucked. I'm asking so I can tell others not to go there.
Because I really believe that your above quote is horrible advice for nearly everyone. (The only exception is pre-meds, for whom college really is bout nothing but grades).
It is not hard to pass. It is not hard to get your degree. In other words, it's easy to get your ticket punched. So don't worry about it! If you focus on learning instead, you will pass. You might not be a purpose-built test-taking machine at the end of each course, so it's possible that your grades will be lower*, but you sure as hell won't fail.
* (but even here, I tend to think that real understanding is quite useful on tests, actually.)
So why worry? "Waste time" on Wikipedia. Take math and physics courses you're not required to. It's worthwhile, and trust me, you'll pass. And it's not like I'm just majoring in Bullshit Studies: this is an E.E. talking.
>
And therein lies another reason to not get a PE. They're your drawings, and you're liable, even if someone changes them to be realistically able to build them. (A junior engineer I believe approved the change btw, or did the change, it's been way too long ago) Either way, this incident finished more than one career.
Interesting... I'd heard the PE described as useless (for E.E.s, and for those intending to get PhDs), but I'd never heard anyone say it could be a bad thing to have one...
>one of which I believe lost his professional practice due to the Hyatt walkway collapse in Chicago
IIRC, the Hyatt walkway collapse happened because of modifications made by the contractor to the original architect's design: A rod was split into two parts in such a way that a nut was required to take twice the force it would have otherwise. But that was the contractor's doing -- I thought.
>Maybe, but this denial of evolution is a US-only phenomena. Could be related to poor US high school education I suppose (since that's the only time most people are going to be taught about it).
>Conversely, at least here in the UK, I know of many religious Christians, including IIRC the Archbishop of Canterbury, and I believe the Pope (obviously he's not in the UK); who accept the theory of evolution with no problems.
This is not because you and your friends are British! It's because you're the type to post on Slashdot (e.g., at least moderately well-educated, and somewhat scientifically or technologically inclined) and they're the type to be your friends!
Slashdot Mirror
Thanks for the links. May be useful in future if I do something like this again. *bookmarks*
Whether Linux is appropriate depends largely on the type of project you're doing. You're probably aware that tons of routers and assorted network gear runs Linux. It might be the best choice if that's what you're doing. But if you're trying to do hard realtime control with Linux... well, if your experience is anything like mine was, it'll be painful.
I did a project with a 266 MHz PII single-board computer once. I chose it because it had tons of on-board A/D and D/A, and when I ordered it I asked the company for their Linux drivers, etc, as well (which they advertised). They sent me a customized version of Redhat to be installed on the development machine, and a bunch of tools to set up a stripped down distro on the target as well, using the same libc libraries, etc.
There were numerous errors in what they sent me, including stupid things like configuration files having DOS instead of UNIX line endings. How this got out the door I do not know. But, I could fix all those dumb oversights, so that wasn't the problem.
The issue was that the distro they sent did not include any realtime extensions (a must for my application), so I endeavored to install RTAI on it. This was where I began to have real problems.
The kernel they were using was old -- 2.2.some-low-number. Assuming this is what their drivers would work with, I found the vanilla source from kernel.org for a nearby 2.2 version, slightly higher, compiled it, no problems. I then tried it with their extra A/D and D/A drivers compiled in: no problems. Then, I tried it with the RTAI extensions (without their extra drivers: Test one thing at a time!) It compiled, but when I tried to run RTAI diagnostic programs the machine would unceremoniously reboot. No good.
"Ok," I thought, "this is a pretty old version of RTAI. Let's try a newer version; maybe that's a little more mature." In order to do that, I needed to use either a 2.4 or a 2.6 kernel. So, I started by trying to build a 2.4 or a 2.6 kernel, again from kernel.org, first, without either RTAI or the extra drivers. First problem: gcc too old. Solution: Compiled on another machine (really, coLinux on my laptop, running Debian Sarge). But after putting the kernel images in the correct locations and reinstalling the boatloader with lilo as you'd expect, the machine would just reboot every time it'd start to execute the kernel. This happened for more permutations than I can remember of 2.4 and 2.6 kernel versions, and configuration options.
Unable to get RTAI working on an old kernel, and unable to get a new kernel to run, (and desperately needing realtime), I ended up putting DOS on the thing and writing code in 16-bit real mode. This gave me essentially unfettered access to the hardware, with fast interrupts, so that, even though people tend not to consider DOS an 'RTOS' per-se, it stayed out of my way enough that I was able to access the hardware directly and run with guaranteeable latencies.
DOS made lots of things harder -- networking and accessing extended memory in particular -- but solving each of those problems proved possible, since I was working with small enough atomic "pieces of the system" that they could be debugged. When I'd been trying to put together linux with RTAI with the given drivers, I was working with a big-monolithic-kernel... running-in-another-mini-kernel, and I could do little more than follow instructions, compile, and pray. If it'd worked, it'd've made my life much easier, but, when it didn't work, I was pretty much at a loss.
If you're on a tight time budget and you've never used embedded Linux before, as much as I love Linux, I've got to say: If you're doing a realtime project, just pay the money for a "real" RTOS.
** If anyone else has had different experiences, I'd be curious to hear them. Though it's too late now, I'd also be curious if anyone has some after-the-fact ideas about why the 2.4 and 2.6 kernels wouldn't execute.
We have rights because we say we do.
From where else can rights come? Natural Law? Please! Not even life itself is a "natural" right: Murder is quite "natural," and it has been the common practice of man to conquer and kill, to rape and pillage, for most of recorded history (and certainly for what came before that too).
It is as we became more civilized that we gave those things up. We, generally, decided those things were wrong. Most of us homo sapiens decided life was a basic right of people. Some of us decided speech was too (but not all of us, for sure); some chose "religion" as well. There's some variety. And in each case, the key is this: We decided.
We humans create the world we inhabit for ourselves. Chalk it up to our opposable thumbs. And the world we inhabit, thanks to our largish frontal cortex, is not just a world of physical stuff, but of ideas, abstractions. The idea of "rights" is an abstraction we built. And we can do whatever we want with it.
So, what do you think your rights should be?
I think that one of mine -- a lesser one, for sure, but still something I'd like -- should be that I can move data around how I want. Not a big deal, and also, I think, not too much to ask. Whether they understand it or not, I'm not in the studios' way. I think they should stay out of mine.
Back in the day, I remember there was a kid, two years younger than I was, in high school band, who "won" such a competition, and became famous for it. Y'see, it was a race. Ever since then, people called him "two stroke." And no, it wasn't an engine reference.
Aye, the heterodyne radio receiver. Yeah, I could see them using a mixer! That doesn't mesh with what's described, but, then, (unless I am missing something), what's described doesn't make a ton of sense:
How can any linear system create an output frequency unequal to one of the input frequencies? I could see rectification as providing a frequency doubling -- but that's old, old news, generates horrid output, and is probably not what's referenced here.From TFA:
So maybe the article gets it wrong, and you're right?
If somebody else could shed some light on this, that'd be cool.
>This sounds a lot like a phased-lock loop.
There's actually no indication of feedback at all here (which is the whole point of a PLL). In general, actually, feedback slows systems down. They do mention that they are using a VCO -- also used in PLLs -- but I get the impression that the purpose here is to, say, generate frequency modulated radio signals; such a modulator would be an open-loop system.
And if it's a truly exceptional girl, the kind who's really your type, she might appreciate one of these:
"Baby, can I be your DNA helicase? 'Cause I want to unzip your genes."
"I wish I were your derivative, so I could lie tangent to your curves."
"If you're sine squared, I want to be cosine squared -- so that together we can be one."
Or, after you've known her for a bit, you could just say something sweet like, "Life without you is like a vector space in which the Cauchy sequence does not converge."
You catch her eye across the room. With a sly grin, you motion for her to walk over to you. It's a simple "I want you over here" hand gesture not unlike -- for a point of reference -- that used by Morpheus in The Matrix duing that famous fight scene.
She crosses the room; now she's standing close to you. "If I could make you come with my finger," you say, "Just imagine what I can do with my whole hand?"
>Yes but most homes in even moderately cold climates will use much more energy for heating than they can get from the sun and thus it will be cheaper to use the solar energy from the sun for heating and then grab the electricity you need of the grid ( which may very well come from super efficient solar collectors).
Ah! Yeah. True, definitely.
Three issues:
In fact, come to think of it, every time I've cited Wikipedia in a paper, I've gotten an A on it. Better, for some of those papers I've received "course citations" -- special notes of positive recognition which are recorded on my transcript. One other professor made a point of stopping me and saying, "This is really a very good paper. Could you make an extra copy of it for me?" I call that success, n'est-ce pas?
I don't just cite Wikipedia, of course. I cite academic papers too. But those papers often don't spell out the basics -- so as an undergrad trying to apply more advanced math, I need some background, and Wikipedia provides that. (Textbooks would too, but it's quicker to go to the Wikipedia article -- and the Wikipedia article is often just as useful if not more). So in the spirit of full disclosure (and the Academic Honor Code), I cite all my sources. That means that, if I need to figure out how the Quaternions work and Wikipedia tells me, I cite Wikipedia.
Admittedly, I'm not researching history or some politically-loaded subject. I'm researching something which benefits from Wikipedia's huge nerd bias. Wikipedia is much more than an encyclopedia: Will I find a complete description of the quaternions in the Encyclopedia Brittanica? What about particle filters? How about the naive Bayes classifier or the ensemble Kalman filter? Wikipedia has those articles! If I go to the article titled State space (controls), Wikipedia goes so far as to show the nonlinear state-space model for a pendulum. I am sure Brittanica doesn't give that.
Librarians keep insisting that people use the Internet as we used Old Media. But it just doesn't work the same. What if some guy on the gamedev.net forum helps me out by sharing an idea with me; should I not cite him? I make a point of including proper footnotes, even for sources like that. Then, it's up to me to make that source authoritative -- by doing a correctness proof in the paper, for example. It takes a little legwork -- but if you immediately write off sources of information like that, you ignore most of the power of the Internet that Old Media lacked. Random, unpublished people know a lot of stuff. You need to verify it often, but it's still useful (and "verification" doesn't necessarily mean "appealing to authority"). As many posters have said, it sometimes just takes critical thinking.
>it will be more economical to use some black paint and water-filled pipes to heat your house than to use photovoltaic cells.
Definitely yes for heating. No, for electricity (at least in principle): Sunlight has a lot of exergy that you waste if you run it through a heat engine on Earth: You're limited by the temperature you can get your hot reservoir. This imposes some fundamental thermodynamic limits:
Via heat engine on earth
Say you use sunlight to heat your 'hot' reservoir to an exceedingly hot temperature. In solar power towers, liquid salt is used, which had a melting point of 1074K -- let's say you get your hot temperature there. Then, say you exhaust heat at room temperature: 22C = 295K. This gives you a Carnot efficiency of deltaT/Th=(1074-295)/1074=73%.
Direct from sun
Solar panels receive radiation from the sun, which is (nearly) a blackbody at 5762K. Again assuming the Earth where you're working is 22C, then you get a Carnot limit of (5762-295)/5762=95%.
So: This doesn't consider the practical efficiencies currently achieved by different technologies, nor the comparative economic efficiencies. But it does show that sunlight has an awful lot of exergy that you throw away by using basically any reasonable heat engine on Earth, and some sort of direct radiation-capturing technology (solar panels, etc) has the potential to be much more efficient.
(woo Thermodynamics.)
When they put it all on one chip, they call it a Microcontroller. When they build it from a few chips, all soldered on a single board, it's called a Single Board Computer. So, this idea is quite widely baked.
(assuming you're not being sarcastic.)
>"Girls on the plus side[:] you can walk all over them and get anything you want."
(punctuation added)
I actually know a guy who does this. He dates pudgy girls who know damn well he could do better -- so they let him get away with murder. It's kind of sick, actually. He gets off on power and treats them like crap.
...because the post is interesting and insightful, and appears to be from someone qualified to say something which is (1) meaningful and (2) different from what everyone else is saying.
It's funny. I only have mod points when I don't want them.
Thus ends my meta-post of the day.
Perhaps one could slap HTTP headers on all traffic, call everything either a GET or a PUT request, and tunnel out with only a modest overhead?
It seems we agree.
This is among the most horrible things I have ever seen.
This is barbarism embraced as heritage.
Racism? This isn't about race. It's about (fucked-up) culture. Much (most?) barbarism happens outside the lines permitted by cultures: There are Americans who torture animals too -- but they are jailed if caught; the culture does not permit it. The problem is when culture encourages this stuff. Bullfighting, in Spain and Mexico, is another example; there is no good excuse for it.
In each case, it is "ethnic identity" which is the excuse used -- a concept which is hugely conflated with "race," but not the same (and that's important). The whole process by which ethnic identity works relies on othering -- defining who is outside the tribe. And race is great for that: it's pretty obvious most of the time. But it's just one way of achieving the more-general goal of defining a them.
So, to justify their dolphin-killing, I am sure that these "fishermen" call it their "heritage:" this is part of ethnic identity, and so relies on defining a them. "What, do you want to not kill dolphins," runs a dialogue which is neither spoken nor even explicitly thought through, "and be like one of those others?" You can insert the name of any derided out-group (local or global) for "others" before: Say, "Koreans," or, "white people."
Now here's the problem with what you said: When you made killing dolphins about race, you used the same kind of "othering" process that those killing them use as their justification. It's tempting, I know [fuck have I had some race issues in my life (interracial dating: didn't think it would be a big deal -- it was)]. But it's the wrong route, because as a side-effect it creates the same us and them categories that provide justification for horrors like this.
There's a huge area within which everything is relative. But outside that, there still exist objective right and wrong. And outside the relative zone, "ethnic identity" creates evil. I don't care if your grandfather did it: Think for yourself.
First, thanks to you and Cthefuture for pointing these out.
The only OSS shooters I was aware of were Cube and its sequel Sauerbraten. Those two are interesting in that they achieve quite a lot with, technically, very little -- the spatial heirarchies they use are quite primitive, and they don't do any occlusion culling, for starters. Cube, the simpler of the two, is actually pretty cool in that it will run, and run well, on damn near anything with a graphics card. Yet it somehow feels like little more than Doom.
So I just tried Warsow and Nexuiz.
Nexuiz: It could be that this game looks great on a monster gaming rig, but me, all I've got is a 3.5-year-old Dell laptop. 2 GHz Pentium M, Geforce somethingsomething mobile (the product numbers in this industry long ago stopped meaning anything: It supports the first version of vertex shaders, and no pixel shaders. UT2004 looks pretty good, and that's about my top end). And on my laptop, Nexuiz was less-than-impressive. In terms of eyecandy-per-dollar-of-computing-hardware, I was underwhelmed. I also agree with Cthefuture that it felt like Quake2.
I was much more impressed by Warsow! It put out nice graphics at a good framerate. It felt a lot like Quake III, with many hints of UT -- but hey, I liked both of those games. Compared to Nexuiz, the "effects" weren't as great, but the quality of artwork was superior: Professional, consistent, and appealing -- and the levels looked better. Unfortunately, there was nobody online to try playing against.
While I'm talking about OSS games -- and I know I'm veering dangerously near the realm of completely off-topic; forgive me, it's cool -- I'd also endorse TASpring. It's a strategy game, not a shooter, and it is also unapologetically a remake of the commercial Total Annihilation -- but it's quite good. Unfortunately, single-player (and the interface for it) is largely neglected, and AI, last I checked, was horrendous. But the multiplayer experience, the graphics, and of course the gameplay (I know: the part they ripped off), are all quite good.
If anyone else knows of any OSS games of Warsow caliber, I'd be curious to see them, whatever the genre.
>In terms of accuracy and surface finish RP models will not be able to match the smooth accurate even surfaces of molded parts, as RP models are created in discrete layers, layer by layer. Until those layers could be brought down extremely small (meaning enormously increasing processing times), the surface finish will always be "rough".
You can imagine schemes besides simple grids which could be faster with some sort of multi-resolution machine. With different-size pixels, you could imagine doing something like the Marching Cubes algorithm, instead of naive rasterization.
Of course, I understand that the layer-based machines couldn't implement that algorithm.
I also wonder if RP is really the right way to go about bringing production into the home. Something more like CNC would be more useful; then it's merely an issue of automation.
>I hope you read the rest of what I wrote there.
I do RTFP, at least!
>you can't really believe that all universities are intending to pump you full of knowledge. That is not the purpose of their business, or how they get funding. Even tuition is just a minor part of the overall funding picture for most universities.
Universities? No. They're cold soulless businesses. But most of the professors I've had have seemed to care quite a bit about their teaching -- though I freely admit that my experience is probably not typical: My university has a highly-ranked undergraduate program, but pretty crappy graduate studies, which explains a lot about which professors then choose to take positions there.
>Yes, you as an individual can work hard, try to pass courses, and try to earn your degree.
Basically what I was saying is that "passing your courses" doesn't take "working hard." Getting As might, but simply passing, at least where I am, doesn't look that hard to do. You know, maybe the reason I don't worry is because of grade inflation! It's this experience that leads me to say, "Even if universities aren't primarily out to teach you, it is a good idea to try to learn as much as you can from them. The grades don't get hugely in the way."
>While it is a good idea to try and pick up some knowledge while you are going through the meat grinder of a college education, you should keep foremost that the knowledge is not the point. The real point is to "punch the ticket"
Where the hell did you go to school? I'm sorry. It sounds like it really sucked. I'm asking so I can tell others not to go there.
Because I really believe that your above quote is horrible advice for nearly everyone. (The only exception is pre-meds, for whom college really is bout nothing but grades).
It is not hard to pass. It is not hard to get your degree. In other words, it's easy to get your ticket punched. So don't worry about it! If you focus on learning instead, you will pass. You might not be a purpose-built test-taking machine at the end of each course, so it's possible that your grades will be lower*, but you sure as hell won't fail.
* (but even here, I tend to think that real understanding is quite useful on tests, actually.)
So why worry? "Waste time" on Wikipedia. Take math and physics courses you're not required to. It's worthwhile, and trust me, you'll pass. And it's not like I'm just majoring in Bullshit Studies: this is an E.E. talking.
> And therein lies another reason to not get a PE. They're your drawings, and you're liable, even if someone changes them to be realistically able to build them. (A junior engineer I believe approved the change btw, or did the change, it's been way too long ago) Either way, this incident finished more than one career.
Interesting... I'd heard the PE described as useless (for E.E.s, and for those intending to get PhDs), but I'd never heard anyone say it could be a bad thing to have one...
>one of which I believe lost his professional practice due to the Hyatt walkway collapse in Chicago
IIRC, the Hyatt walkway collapse happened because of modifications made by the contractor to the original architect's design: A rod was split into two parts in such a way that a nut was required to take twice the force it would have otherwise. But that was the contractor's doing -- I thought.
>Maybe, but this denial of evolution is a US-only phenomena. Could be related to poor US high school education I suppose (since that's the only time most people are going to be taught about it).
Not really; you'd be surprised.
>Conversely, at least here in the UK, I know of many religious Christians, including IIRC the Archbishop of Canterbury, and I believe the Pope (obviously he's not in the UK); who accept the theory of evolution with no problems.
This is not because you and your friends are British! It's because you're the type to post on Slashdot (e.g., at least moderately well-educated, and somewhat scientifically or technologically inclined) and they're the type to be your friends!
Because actually, the stats tell the same story about the UK that they do about the US.
It's true that most Americans are bleeding idiots, but that's not a trait of Americans so much as it is of Homo Sapiens.