To be honest, I couldn't stand chemistry lab either. (I AP'ed out of intro chem, but I took organic chemistry and discovered there that I hated chemistry with a fiery vengence). However, tedious, boring labs aren't restricted to chemistry. Most of my EE labs were just as tedious and boring. If I hadn't known that these labs weren't representative of what a practicing electrical engineer does in the workplace, it may very well have put me off on EE. I'm sure many other people who enter college with a passion for electronics switch out of EE because of the torrents of poorly-explained equations and the tedium of labs. Innovative and interesting courses like 6.002X could help stop the bleeding.
So basically we agree, which is always a good thing.;-) Also, I should hope that I would know a little bit about optics, or these folks would have to take back my degree...:-p
Do you still remember how to isolate and identify the compound? Unless you're a chemistry major, I'd wager that you don't, so the whole thing ended up being a pointless hoop you had to jump through and probably put you off on chemistry for life. On the flip side, HardCase probably remembers how to make slime and probably won't go postal if you ask him to do a little chemistry.:-p
In my experience, EE labs are spent building circuits, not because they're interesting, but for the sake of building circuits--how often is a practicing electrical engineer going to design or build a circuit is consists solely of carbon resistors connected to a power supply? To be honest, I remember very little about circuit theory beyond voltage and current dividers because I had the theory lectured to me, but I didn't have an interesting project to which to apply the theory. For example, I'd probably remember filter design a lot better if I had to use it to build the tuning circuit for a radio instead of using it to build a lab circuit on a breadboard. Being able to apply theory to a practical situation also helps a student develop a intuitive feel for the theory, which is vital to the practicing engineer.
I'd wager that the majority of new EE graduates wouldn't be able to explain how a radio works, and that most of the grads who could could have done so before they started their degree. I'd also wager that most of the MIT students taking this course didn't understand how a radio worked on the first day of class, but now they do, which means that now they're well ahead of the curve.
Since all mirrors with finite apertures suffer from diffraction blurring, we can neglect the blur due to spherical aberration as long as it is less than the diffraction blur. Then we can say that the focus is located halfway between the mirror and its center of curvature without reservation. When spherical aberration becomes comparable to or exceeds diffraction, then we can identify several foci: paraxial focus (at half the radius of curvature from the mirror), marginal focus (which is slightly closer to the mirror), and the circle of least confusion (which is between paraxial and marginal focus). We can still say with certainty that paraxial focus is at half the radius of curvature of the mirror, but we may get a sharper image if we displace our image plane from paraxial focus (say to the circle of least confusion). Exactly where we want to position the image plane will depend on the application--the circle of least confusion is great for photography, but there are better image plane locations to use for resolving point objects like stars.
At the end, I could tell you the boundary conditions at a air/reflector interface, but I couldn't tell you where the damn mirror actually focused the light.
For your information, the focal length of a spherical mirror is half the radius of curvature.
In defense of the curriculum for your optics course, understanding the electromagnetic theory of light is vital for understanding the intersection of electronics and optics (fiber optic communication, lasers, photosensors, etc). In most of these equations, many of the same approaches used to analyze microwave and radio can be used, it's just that the wavelength is much shorter. In the case of photolithography, electromagnetic wave theory is needed to determine the resolution of an imaging system like a projection system for photolithography, which in turn limits the feature size. The theory behind this is directly analogous to the theory explaining the resolution limits of radar. To be honest, ABCD matrices and lens equations and such don't really need that much coverage--maybe a week or two of lecture and a problem set or two to get familiar with using them. If you ever need to use the ABCD matrices or lens equations, you can always look them up.
If you really want to learn lens design or otherwise specialize in optics should go to schools like my alma mater or possibly our intellectual rival.
Some things that are lacking in EE: Motors of any kind, a focus on Controls, Real life transmission lines, rather than all microstrip lines, and more early EE classes. We didn't start circuits until Sophomore year. True, my university is changing the program, but this is a widespread problem that needs addressed in order to keep the world supplied with competent Engineers.
Motors: Mechatronics (which includes electric motors) have more or less moved into the domain of mechanical engineering.
Controls: This is another bastard stepchild of mechanical engineering and EE. At my alma mater both the EE department and the mechanical engineering department offered courses on controls, but controls was only required for mechanical engineers.
Real-life transmission lines, rather than all microstrip lines: The demand for engineers trained in power transmission ("real-life transmission lines") in the U.S. is maybe a handful a year, whereas microstrip theory is vital for digital design now that microprocessors operate at frequencies where the lumped element model is no longer valid, so every interconnect is basically a microstrip waveguide
We didn't start circuits until sophomore year: This is pretty much standard in EE curricula. You really do need a year of calculus and physics under your belt before you're ready for introductory circuits. The calculus is necessary to analyze the transient behavior of inductors and capacitors, and the physics establishes the physical origin of inductance and capacitance.
I hope you don't plan to major in engineering. Theory is important, but experimental or "hands-on" intution is a vital for any engineer. Otherwise, as the Purdue example illustrates, you will spec something for your design which is physically unrealizable, or is too expensive, too large, too heavy or otherwise ill-suited for your application.
School machines are the most economical and for the most part the most convenient computing solution, but one thing about college is that everyone tends to have papers or projects due at the same times. When paper or project times roll around, availability of school computers can be a problem. This is the fundamental reason for owning one's own computer--it's always available for you to use when you need it. At large universities, owning your own computer can be a lifesaver.
Re:See outside the bubble?
on
Mastering Light
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· Score: 2, Informative
Infrared is not a single color. It is a range of colors. The warmer something is the closer it gets to a visible color.
I think you are confusing the infrared spectrum with the concept of color temperature. The idea of color temperature arises naturally from blackbody radiation--as a blackbody radiator gets hotter, its peak emission wavelength gets shorter. If it's hot enough, it picks up a distinctive color (for example, blackbodies look red around 3000 Kelvin, IIRC, and yellow around 6000 Kelvin). It does not mean that the infrared spectrum suddenly becomes visible to the unaided human eye, it just means that the blackbody is now radiating visible wavelengths strongly enough that the eye can see them. The infrared spectrum is completely decoupled from the concept of color because, by definition, the infrared spectrum consists of wavelengths too long to be seen by the unaided eye.
Actually, electric generators are quite efficient (probably in the neighborhood of 80-90%), whereas internal-combustion engines are pretty inefficient (probably 20%). If internal-combustion was any where near as efficient as electric power generation, we would have gasoline engines powering all household appliances (refrigerators, washer/dryer, etc), but obviously that is not the case.
I use opera, which has pop-up blocking built-in, but some ads can not be blocked. I've noticed that pop-ups have become more code intensive and actual open as an element of the page itself. These usualy have a convenient little "close" link, but it still appears, and many are in the middle of the page so it's very easy to accidentaly click the link while it is rendering.
They sound like the Macromedia Flash-based Shoshkeles which appeared as a Slashdot story a while back. I just don't have Flash installed with Mozilla, so I don't see those, either...:-)
Re:Modern origami artists familiar with math
on
Origami and Math
·
· Score: 1
Mr. Montroll constructs his art completely from folds (never cuts) on rectangular (not oddly shaped) origami paper.
In fact, most of Montroll's models are folded from simple squares (unlike Mr. Lang, who uses some of the strangest aspect-ratio rectangles I've ever heard of). I got started on Montroll's Animal Origami for the Enthusiast when I was in elementary school and have been hooked ever since. I can still fold the Tyrannosaurus Rex and Brontosaurus models from memory.
Therefore, Pi is irrational BUT!ALSO! Pi is not constructible. Like, say, sqrt(2) is the hypotenuse of right triangle with legs equal to 1. (To the guy who says it can be computed) Pi cannot be computed (see sentence about triangles and stuff)!
How is constructing an isoceles right triangle to compute sqrt(2) different from constructing a circle to compute pi?
Not to mention that takeoff and landing are the twitchiest phases of flying any aircraft. Surely one can afford a few minutes without the use of his electronic security blankets? (especially if it increases the probability that he will live to use them the next day)
You don't know what codec was used in an avi until you download it, and find it's some obscure 2 year old version of divx which doesn't work anymore. Doh!
I had that same problem for the longest time until I discovered FFDShow and 3ivX, both of which handle DivX 3/4/5 like a champ (unlike the official DivX codec:-p). For files where the audio track doesn't seem to work, installing the Morgan Stream Switcher in the Nimo Codec Pack seems to fix that.
128k AAC is still better than 128k MP3, but how many people are going to believe that when most people assume that a 2ghz Pentium is faster than an AMD processor running at a lower clock speed?
Seeing all the 128 kbps and lower bitrate MP3 files circulating on most filesharing networks, most people don't know the difference and don't care.
Second, who is going to pay 99 for something they can get for free on Gnutella?
99 is a pretty happy medium between starving an artist by downloading a song from KaZaA or Gnutella and lining record executives' pocketbooks by paying $7 for a CD single. Giving consumers another option is certainly a good thing.
I believe that loss of quality generally occurs when converting from one lossy compression format to another. By definition, the information that is lost in compression cannot be recovered by using a different compression algorithm, so you can't improve the quality of a given file by converting from AAC to MP3--you can only break even or do worse. Now whether or not the loss of quality is perceptible is subject to debate, but certainly converting from AAC to MP3 would require increasing the file size or losing fidelity or both.
It should be noted that most headphones and computer speakers are pretty low-fidelity, so any loss of quality due to encoding will probably be masked by the poor response of the headphones or speakers. In your car, any encoding artifacts are likely to be swamped by road or wind noise. So loss of quality due to encoding probably isn't as bad as the parent poster makes it out to be.
You can't do any of the following legal things without significant loss of quality...
And Apple is obligated to enable lossless conversion to other formats why? They obviously have an incentive to promote their own products and formats, and they are within their rights to do so. You can still convert these files to MP3 or another format with some loss of quality, or you could buy a CD and make your own high-quality encodes with some additional expense. Certainly, you cannot deny that this is a more sensible approach to artists' digital copyrights than SDMI, non Red Book compliant CDs, or Windows Digital "Rights" Management.
I agree--Comcast service in the Ann Arbor area is pretty bad. Before they deployed their upgraded network a month or two ago, I would regularly get speed test results of 200 kbps or less from broadbandreports.com, and that went on for 6 months. Even now, I occasionally get speed test results less than 100 kbps. When I call tech support to check on their network status and to complain about such lousy network performance, the only diagnostic proceedure they offer is to reset the modem and to hope that makes the problem go away.
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To be honest, I couldn't stand chemistry lab either. (I AP'ed out of intro chem, but I took organic chemistry and discovered there that I hated chemistry with a fiery vengence). However, tedious, boring labs aren't restricted to chemistry. Most of my EE labs were just as tedious and boring. If I hadn't known that these labs weren't representative of what a practicing electrical engineer does in the workplace, it may very well have put me off on EE. I'm sure many other people who enter college with a passion for electronics switch out of EE because of the torrents of poorly-explained equations and the tedium of labs. Innovative and interesting courses like 6.002X could help stop the bleeding.
So basically we agree, which is always a good thing. ;-) Also, I should hope that I would know a little bit about optics, or these folks would have to take back my degree... :-p
Do you still remember how to isolate and identify the compound? Unless you're a chemistry major, I'd wager that you don't, so the whole thing ended up being a pointless hoop you had to jump through and probably put you off on chemistry for life. On the flip side, HardCase probably remembers how to make slime and probably won't go postal if you ask him to do a little chemistry. :-p
In my experience, EE labs are spent building circuits, not because they're interesting, but for the sake of building circuits--how often is a practicing electrical engineer going to design or build a circuit is consists solely of carbon resistors connected to a power supply? To be honest, I remember very little about circuit theory beyond voltage and current dividers because I had the theory lectured to me, but I didn't have an interesting project to which to apply the theory. For example, I'd probably remember filter design a lot better if I had to use it to build the tuning circuit for a radio instead of using it to build a lab circuit on a breadboard. Being able to apply theory to a practical situation also helps a student develop a intuitive feel for the theory, which is vital to the practicing engineer.
I'd wager that the majority of new EE graduates wouldn't be able to explain how a radio works, and that most of the grads who could could have done so before they started their degree. I'd also wager that most of the MIT students taking this course didn't understand how a radio worked on the first day of class, but now they do, which means that now they're well ahead of the curve.
Since all mirrors with finite apertures suffer from diffraction blurring, we can neglect the blur due to spherical aberration as long as it is less than the diffraction blur. Then we can say that the focus is located halfway between the mirror and its center of curvature without reservation. When spherical aberration becomes comparable to or exceeds diffraction, then we can identify several foci: paraxial focus (at half the radius of curvature from the mirror), marginal focus (which is slightly closer to the mirror), and the circle of least confusion (which is between paraxial and marginal focus). We can still say with certainty that paraxial focus is at half the radius of curvature of the mirror, but we may get a sharper image if we displace our image plane from paraxial focus (say to the circle of least confusion). Exactly where we want to position the image plane will depend on the application--the circle of least confusion is great for photography, but there are better image plane locations to use for resolving point objects like stars.
In defense of the curriculum for your optics course, understanding the electromagnetic theory of light is vital for understanding the intersection of electronics and optics (fiber optic communication, lasers, photosensors, etc). In most of these equations, many of the same approaches used to analyze microwave and radio can be used, it's just that the wavelength is much shorter. In the case of photolithography, electromagnetic wave theory is needed to determine the resolution of an imaging system like a projection system for photolithography, which in turn limits the feature size. The theory behind this is directly analogous to the theory explaining the resolution limits of radar. To be honest, ABCD matrices and lens equations and such don't really need that much coverage--maybe a week or two of lecture and a problem set or two to get familiar with using them. If you ever need to use the ABCD matrices or lens equations, you can always look them up.
If you really want to learn lens design or otherwise specialize in optics should go to schools like my alma mater or possibly our intellectual rival.
I hope you don't plan to major in engineering. Theory is important, but experimental or "hands-on" intution is a vital for any engineer. Otherwise, as the Purdue example illustrates, you will spec something for your design which is physically unrealizable, or is too expensive, too large, too heavy or otherwise ill-suited for your application.
School machines are the most economical and for the most part the most convenient computing solution, but one thing about college is that everyone tends to have papers or projects due at the same times. When paper or project times roll around, availability of school computers can be a problem. This is the fundamental reason for owning one's own computer--it's always available for you to use when you need it. At large universities, owning your own computer can be a lifesaver.
Actually, electric generators are quite efficient (probably in the neighborhood of 80-90%), whereas internal-combustion engines are pretty inefficient (probably 20%). If internal-combustion was any where near as efficient as electric power generation, we would have gasoline engines powering all household appliances (refrigerators, washer/dryer, etc), but obviously that is not the case.
Not to mention that takeoff and landing are the twitchiest phases of flying any aircraft. Surely one can afford a few minutes without the use of his electronic security blankets? (especially if it increases the probability that he will live to use them the next day)
I believe that loss of quality generally occurs when converting from one lossy compression format to another. By definition, the information that is lost in compression cannot be recovered by using a different compression algorithm, so you can't improve the quality of a given file by converting from AAC to MP3--you can only break even or do worse. Now whether or not the loss of quality is perceptible is subject to debate, but certainly converting from AAC to MP3 would require increasing the file size or losing fidelity or both.
It should be noted that most headphones and computer speakers are pretty low-fidelity, so any loss of quality due to encoding will probably be masked by the poor response of the headphones or speakers. In your car, any encoding artifacts are likely to be swamped by road or wind noise. So loss of quality due to encoding probably isn't as bad as the parent poster makes it out to be.
The truly beautiful hacks were the Cathedral of Our Lady of the All-Night Tool and the campus police car on the Great Dome. This one was cute, but it doesn't even compare to the One Ring on the Great Dome.
Yes, but it would take more energy to disassociate the water into hydrogen and oxygen than you get in the form of fuel. There still is no free lunch.
I agree--Comcast service in the Ann Arbor area is pretty bad. Before they deployed their upgraded network a month or two ago, I would regularly get speed test results of 200 kbps or less from broadbandreports.com, and that went on for 6 months. Even now, I occasionally get speed test results less than 100 kbps. When I call tech support to check on their network status and to complain about such lousy network performance, the only diagnostic proceedure they offer is to reset the modem and to hope that makes the problem go away.