There's a great example of this in a book called "The Origin of Wealth" by Eric Beinhocker (a great book, actually).
In Chapter 8, he shows graphs of IBM's stock price over a period of time and a random walk. They look very similar and I think it would be hard to tell them apart. However the next set of graphs show "Changes in Stock Price" for IBM vs the random walk and the difference is stark. The real random walk had a very wide band of nearly uniform "fuzziness" about the origin. The real one, however, had a much narrower band of fuzziness with many large spikes in either direction.
There are scores of things that would fall under this category. Killing kittens, having sex with his mother, watching WWE come to mind.
These things, when done in the home, are not the purview of the school. They may be legal issues, but if so, should be handled by the proper legal authorities, not some school administrator with an Orwellian streak. The school has no jurisdiction over the home or anywhere else that isn't the school.
Now, if the kids are killing kittens or having sex with their mothers at the school, then that is the only time the school administration should be involved.
Or maybe a format like "I, Claudius" where there are several episodes, a few main characters and many other changing characters. It was also low budget-looking and had few special effects, and that seems to match better the events in the Foundation stories. Sure you can make it 3d, but the stories have so little action that I'm not sure I see the point.
It's an interesting talk about how while schizophrenia may be the result of a full expression of a recessive gene, the schizotypal may be a mild expression of the same gene, leading to people like shamans. That would tend to support your "born with a strong propensity"...
The same boomers that participated in Woodstock ended up voting for Reagan and Bush.
Not necessarily. The number of people at Woodstock is in the thousands while the number of boomers is in the millions. There were plenty of people at the time who thought the people going to Woodstock were a bunch of "damn dirty hippies", and plenty more that had never even heard of it until well after the fact.
It could be an interesting thing to research but I suspect that the people who voted in Reagan and Bush were, for the most part, not the same people who attended Woodstock.
Also this scanning technology doesn't only work at airports. It works exactly the same at train stations. If people stop using planes and go back to trains then they'll just move the scanners over to the train station.
While there's certainly lots of great government money for the sellers of these machines, they won't be as useful for trains. It's much easier to disable a train by damaging the tracks ahead of it rather than trying to blow it up. So if you're intent on taking out a train, why bother with the risk of trying to get on-board with a bomb when there's thousands of miles of tracks with much easier and anonymous access.
That's why ROI is a limited way to value things. And it's a stupid thing to use as the only measure of value.
It's more complicated but you really need to apply risk to the situation. The return on the backups is only 0 if there were no failures requiring backups. When you use risk in the analysis, you can then consider that there are n1 events requiring backup that would save x1 number of dollars of re-work. There are n2 events requiring backup that result in x2 lost dollars from being unavailable to do business, and so on. With probability of events and costs/benefits of those events, you can then come up with an appropriate value of the IT services.
If the cost of fail-over on a webserver is $x, and you make $n of revenue per hour, and it would take y hours to rebuild and deploy a webserver, then if $x * probability of failure $n * y, then you have a pretty good justification for paying in advance for fail-over.
You can use an even more sophisticated "real options" analysis if you want to get fancy.
If not, go to a Walmart and pick up a prepaid phone for $20
I actually recently switched from Virgin Mobile's prepaid service to the Straight-Talk service offered through Walmart. I actually got the $90 Samsung R451C phone with a slide-out keyboard and that can surf the internet. I chose the $45/month service, which allows for unlimited everything (voice, data, texts, internet, etc). The service has been great - it uses Verizon's network (somehow though Net10).
My biggest complaints: I can find no way to manipulate the address book with software like Bitpim. There are not separate volume settings for speakerphone, external headset, and normal earpiece, so I'm always having to adjust the volume. And while you can put any mp3 or midi and have it be a ringtone, there appears to be no way to put games or other apps on the phone. Also, if you do the $30/month plan (1000 minutes, texts), you get an annoying minute warning before each call (this goes away with the $45 unlimited plan). I also think there's no way to tether the phone.
Overall, I've been very happy with this phone and service.
Is it possible that you are replying to a comment from a different article entirely?
Did you read you own post that I responded to? A couple posts up, someone said that applicants should use an email from their own domain so they can push traffic to their domain. The response was that not everyone has the time or money to manage a domain [that would represent them well while applying]. YOU said [about people who don't have the time or money to run their own personal web servers], "And these are not the people I want to hire to maintain my web servers". So yeah, I'm responding to you. What does what they do as a hobby, in their free time (when they should be maintaining these personal servers of theirs) have to do with their ability to professionally run yours?
Poor attention to detail... it's hard to work with people like that.
And these are not the people I want to hire to maintain my web servers.
Really? Ostensibly, you'd be paying them to maintain your web servers. Their personal web space would essentially be a hobby. Maybe, just maybe, they have other interests outside of their professional domain. I would rather hire someone who has a proven professional track record of maintaining web servers than someone who only has a pretty personal hobby-page. If all they do is run web servers, even as a hobby, they're more likely to burn out and they're less likely to have interests in common with clients.
I manage supply chains in my professional life. It would be pretty odd for a potential employers to expect me to do the same in my private life. In fact they might suspect that I was spending "work time" managing my other business. I mean, where do you draw the line? Does this potential employee's website have to have customers? Fail-over, backup, load-balancing, etc? Or will their personal site not be up to snuff?
And really, what does having a personal website have to do with running web servers?
That's okay though - it's a self-selecting process. You don't sound like the kind of person a happy, well-adjusted person wants to work for anyway.
Wow, this is kind of like when the unstoppble force meets the immovable object.
I'm sure the solution will be to have TSA officers carefully gird children with special lead loin cloths to cover their naughty bits before they are put through the scanner.
I missed the boat on buying stock in full-body scanner companies, but I may still be able to make a killing on the lead bathing suit manufacturers.
Take other classes, like Econ 101. Get a broad education, and with real life applicability.
Plus the chicks are hotter
If you want the hottest chicks, you really need to take classes in the education department, like theory of development. If you take elementary ed classes, you'll actually get college credit for finger painting and making paper mache masks. And be in classes with hot girls.
I'd also recommend taking a look at Ars Digita University's old Computer Science materials at http://aduni.org/.
The discrete math course has nice videos of the lectures, so it could be a nice way to augment whatever course someone takes live. Plus there are additional problems (some with answers). And the book for the course, being 10 years old, can be picked up for under $10.
You also saw Computer Science coming out of math departments as well. Where I was going to school in the 70s, Computer Science was under math, but Computer Engineering was being built in the Engineering department. There was certainly some overlap. My guess is you saw it coming out of whichever department had the most clout and desire to have it.
It doesn't even have to be anthropogenic climate change.
Any significant climate change, regardless of the source, has the potential to wreak havoc on the economy and that impacts national security. Food security is a large part of national security and when zones for growing key crops changes, we might not be able to respond fast enough. Changes in climate will also most likely effect availability of water. California has been in a drought for several years now. It's also a key food-producing region. A long-term change in precipitation patterns could devastate the agriculture there.
Higher sea temperatures will lead to more energetic hurricanes, which definitely will effect the gulf and south-eastern seaboard of the US. And of course rising sea levels will impact any of the cities near sea level and will probably lead to salinization of currently fresh-water marshes near the ocean.
Even if you deny the probability of anthropogenic impact on the climate, the "natural swings" in the climate can still have a large impact on the security of the nation. Therefore, it IS within the scope of the CIA's work to keep an eye on it.
And of course, this is just looking at the direct impacts on the US. These same climate-related problems will be global in nature and that will also have a destabilizing effect on governments around the world; both ones we like and ones we don't.
In short, Sen. Brasso is an idiot. Anything that can severely impact national security is clearly in the purview of the CIA.
The subway in Paris had tall narrow gates that would open (rather than a turnstyle). That worked really well and would keep all but the most aggressive from jumping over. They were at least 6 feet tall.
Sure, it would be inconvenient, but not as inconvenient as having the terminal emptied.
Most of their products are very low quality anyway and end up costing more in the long run.
Well, they are Chinese factories, but most often it's American/Western companies who are providing designs, specifying materials, and ordering products. The products low quality is not due to the Chinese - who can make things at any level of quality, but the American companies who set the bar as low as it is.
When your pair of Chinese-made Nike or Adidas shoes fall apart, it's because of the design and materials specification.
And why do the western companies do this? (specify cheap low quality products) Because that's what sells in America. Americans either don't want or can't afford quality. They flock to Walmart because they'd rather buy a cheap plastic piece of crap product rather than a durable quality product.
You allude to a situation I heard in a story once (and can't quickly find) that comes down to work boots. A poor man always has to buy the cheapest boots because that's all he can afford. A richer man can buy a good quality pair of boots, even though they cost much more. In the long run, however, the poor man will have ended up paying much more for boots because he has to keep buying replacements.
So we (Americans), end up buying so much cheap low-quality stuff not so much because it's Chinese, but because we vote with our dollars and keep buying it. We don't complain about the quality or demand better products, but instead run in herds to Walmart to get the $25 POS DVD player. And of course it's a vicious cycle... who can afford to stock and sell quality products when you don't have buyers to support your business? It's a "race to the bottom".
Dammit, by the circular firing-squad nature of this discussion, it's clearly a scheme hatched by The Left. Nobody can snatch defeat from the jaws of victory like the Democrats.
Do you see this with all LEDs? Or just some? My understanding is that LEDs use DC current to work (being a diode, the current only flows in one direction).
I've noticed differences between sets of Christmas LED lights and I assumed the flickering was from using a cheaper half-wave rectifier to convert the AC wall current to a DC signal for the LEDs. Using a half-wave rectifier would mean they were only on during half the AC cycle and off during the other half (this only needs 2 diodes). With a full wave, you need 4 diodes, but you have the lights on through the entire AC cycle, except for the moments where the wave is at 0 voltage. Even that can be fixed using coils and capacitors to smooth the signal out.
However, I would think that LEDs powered from a DC source, such as a car battery, would not exhibit the flickering.
Red-green colorblindness should not affect the ability of a person to correctly observe a traffic light.
Under ideal conditions, you're correct. (But this whole article is about non-ideal conditions)
I have some color blindness and I can describe the problem I have. When it's raining and at night, it's difficult for me to tell a green light (non LED) from a nearby street illumination light (from a distance). I know that sounds crazy. Because it's dark, it's hard to see the rectangular enclosure, so I can't tell by the green-light's position. Only after it's changed to yellow then red can I tell which light was the illumination light and which was the green light.
And I can't just assume that lack of a yellow or red means I have the green, because it might be burned out.
The new LED lights use a different color of green that has a higher blue component that makes them completely obvious. Plus the LED lights are more intense than the other lights. This may be due to the light from an LED being a smaller set of frequencies (or a single one?) compared to a filtered incandescent, though I really don't know much about the physics of LEDs.
So, I expect it was mentioned in this context because when it's dark it's harder to tell the position of the green light against the dark enclosure, especially when there are nearby white lights. And the blue-green used makes them easier to see. At least that's my experience.
It is one thing to update tech if it gives significant improvement in functionality, but, just doing it to be fashionably 'green' is not the way to do IMHO.
From the traffic manuals I've helped write, the LED traffic lights do indeed offer significantly improved functionality over incandescent lights in ways that are not related to "being green".
Actually, the "green" is a bluish color of green that makes it easier for people with color deficiency to tell from nearby white street lights (this is huge, being somewhat color blind myself - suppose it's raining at night and there are street lights near the stop light. For me, it's sometimes difficult to distinguish the green light from the nearby street light; only when it turns yellow and red can I tell which one belongs to the stop light. With the new ones, I have no problem at all.)
They're also made up of many LED elements per "light" so that when one inevitably burns out, most of the light still functions before a replacement can be done (say one of the green LEDs burns out - you still have several green LEDs working). With incandescent, when you lose red, you lose it completely. This improves safety for drivers and allows more flexibility in scheduling the work crews to replace the lights.
The LED lights are also brighter and more intense than the incandescent lights, making them more visible from farther way and in a wider range of ambient light conditions. (The incandescent lights don't do very well when the sun is directly behind you as you face a light - I think part of this is that the incandescent lights have a reflector behind the bulb, like a flashlight does - so the sunlight enters the lens from the front and then reflects back out. The LEDs don't have this reflector around the bulb).
Plus, the LED lights last significantly longer than the incandescent lights. You save money on the labor of replacing them - as well as reducing the safety risks to the work crews who have to go work in the street.
Of course, every new technology has unanticipated side effects, and the inability of the LED lights to melt off snow is one of them. But really, that's just an engineering problem that several people here have already suggested good solutions for.
In a similar vain, when I worked as a sysadmin at a university, we had a computer lab with 30 computers and we had the heat (old water pipes) permanently turned off because the monitors gave off enough heat to keep the room comfortable, even in winter. After we switched to LCD monitors, students started complaining that the lab was always too cold and we had to have maintenance come in and bring the heat back online. Likewise, an unintended consequence of a newer technology.
I don't think the terrorist recruiters are specifically seeking out Engineering students.
Based on my experience working in a University (and attending a couple) it seems to me that students who get sent abroad from Islamic countries study Engineering because it's a particularly useful degree back home. Many of these countries are underdeveloped and bringing back good engineering skills is a way to work towards correcting that. You just don't see as many students from the developing world here in the US getting degrees in art, English, or the social sciences.
Now, I if I were an Islamic terrorist recruiter, I'd most interested in finding people who had lived in the target country and could move around comfortably there. But they'd also need to be people who were grounded in Islam and hopefully susceptible to a more fundamentalist point of view. Young people tend to be more "flexible" in their theology than older people. So, who do I look for? Students from my own country who have been or are currently studying abroad and most of them are going to be Engineers. Plus these students have the added benefit of having already gone through the visa process and will probably much easier to get back into the target country.
I really don't think the recruiters and leaders are looking specifically for highly trained engineers so they can be expended on the front-line. If Engineers are actually valued for their technical skills, planning capability, etc, I'd use them for designing IEDs and planning operations. Considering the failures and apparent incompetence so far, maybe they are using the "bottom of the barrel" for the actual operations, since they have the qualifications to reach the target country but are not so capable in an Engineering capacity.
I have been working IT for 20 years now and have ruined many nice silk ties on rough server cases. Switched to "cheap ties" but they still add up.
Your company should be picking up the cost of those ties. If they require you wear them and they are made unserviceable by the work you are required to do, then it's their responsibility. Heck, even the army, which is generally a crappy employer, will replace your stuff when it gets messed up at work.
There's actually an interesting Agent-Based Simulation system based (loosely) on Logo called NetLogo (http://ccl.northwestern.edu/netlogo/). You can do basic Logo stuff, but it can actually do some very sophisticated modeling and the syntax is not very difficult.
Using syntax similar to Logo, you have program agents to sense their environment and then take action based on that. The concepts scale well to other platforms like the Lego Mindstorms.
It's not a traditional programming environment but as a beginner you'd still need to understand the idea of variables, objects, and conditional logic. Plus it's very visually oriented and has many examples that a kid can play with and tweak.
Slashdot Mirror
There's a great example of this in a book called "The Origin of Wealth" by Eric Beinhocker (a great book, actually).
In Chapter 8, he shows graphs of IBM's stock price over a period of time and a random walk. They look very similar and I think it would be hard to tell them apart. However the next set of graphs show "Changes in Stock Price" for IBM vs the random walk and the difference is stark. The real random walk had a very wide band of nearly uniform "fuzziness" about the origin. The real one, however, had a much narrower band of fuzziness with many large spikes in either direction.
Here's a link on Google Books to those pages:
http://books.google.com/books?id=eUoolrxSFy0C&lpg=PP1&dq=%22origin%20of%20wealth%22&pg=PA176#v=onepage&q=&f=false
There are scores of things that would fall under this category. Killing kittens, having sex with his mother, watching WWE come to mind.
These things, when done in the home, are not the purview of the school. They may be legal issues, but if so, should be handled by the proper legal authorities, not some school administrator with an Orwellian streak. The school has no jurisdiction over the home or anywhere else that isn't the school.
Now, if the kids are killing kittens or having sex with their mothers at the school, then that is the only time the school administration should be involved.
Or maybe a format like "I, Claudius" where there are several episodes, a few main characters and many other changing characters. It was also low budget-looking and had few special effects, and that seems to match better the events in the Foundation stories. Sure you can make it 3d, but the stories have so little action that I'm not sure I see the point.
Here is an interesting lecture by Robert Sapolsky, "Evolution, religion, schizophrenia and the schizotypal personality", http://www.boingboing.net/2009/06/06/evolution-religion-s.html
It's an interesting talk about how while schizophrenia may be the result of a full expression of a recessive gene, the schizotypal may be a mild expression of the same gene, leading to people like shamans. That would tend to support your "born with a strong propensity"...
His recent graduation day talk at Stanford was, while not related (on the uniqueness of humans), even more interesting:
http://www.youtube.com/watch?v=hrCVu25wQ5s
The same boomers that participated in Woodstock ended up voting for Reagan and Bush.
Not necessarily. The number of people at Woodstock is in the thousands while the number of boomers is in the millions. There were plenty of people at the time who thought the people going to Woodstock were a bunch of "damn dirty hippies", and plenty more that had never even heard of it until well after the fact.
It could be an interesting thing to research but I suspect that the people who voted in Reagan and Bush were, for the most part, not the same people who attended Woodstock.
Also this scanning technology doesn't only work at airports. It works exactly the same at train stations. If people stop using planes and go back to trains then they'll just move the scanners over to the train station.
While there's certainly lots of great government money for the sellers of these machines, they won't be as useful for trains. It's much easier to disable a train by damaging the tracks ahead of it rather than trying to blow it up. So if you're intent on taking out a train, why bother with the risk of trying to get on-board with a bomb when there's thousands of miles of tracks with much easier and anonymous access.
That's why ROI is a limited way to value things. And it's a stupid thing to use as the only measure of value.
It's more complicated but you really need to apply risk to the situation. The return on the backups is only 0 if there were no failures requiring backups. When you use risk in the analysis, you can then consider that there are n1 events requiring backup that would save x1 number of dollars of re-work. There are n2 events requiring backup that result in x2 lost dollars from being unavailable to do business, and so on. With probability of events and costs/benefits of those events, you can then come up with an appropriate value of the IT services.
If the cost of fail-over on a webserver is $x, and you make $n of revenue per hour, and it would take y hours to rebuild and deploy a webserver, then if $x * probability of failure $n * y, then you have a pretty good justification for paying in advance for fail-over.
You can use an even more sophisticated "real options" analysis if you want to get fancy.
If not, go to a Walmart and pick up a prepaid phone for $20
I actually recently switched from Virgin Mobile's prepaid service to the Straight-Talk service offered through Walmart. I actually got the $90 Samsung R451C phone with a slide-out keyboard and that can surf the internet. I chose the $45/month service, which allows for unlimited everything (voice, data, texts, internet, etc). The service has been great - it uses Verizon's network (somehow though Net10).
My biggest complaints: I can find no way to manipulate the address book with software like Bitpim. There are not separate volume settings for speakerphone, external headset, and normal earpiece, so I'm always having to adjust the volume. And while you can put any mp3 or midi and have it be a ringtone, there appears to be no way to put games or other apps on the phone. Also, if you do the $30/month plan (1000 minutes, texts), you get an annoying minute warning before each call (this goes away with the $45 unlimited plan). I also think there's no way to tether the phone.
Overall, I've been very happy with this phone and service.
Is it possible that you are replying to a comment from a different article entirely?
Did you read you own post that I responded to? A couple posts up, someone said that applicants should use an email from their own domain so they can push traffic to their domain. The response was that not everyone has the time or money to manage a domain [that would represent them well while applying]. YOU said [about people who don't have the time or money to run their own personal web servers], "And these are not the people I want to hire to maintain my web servers". So yeah, I'm responding to you. What does what they do as a hobby, in their free time (when they should be maintaining these personal servers of theirs) have to do with their ability to professionally run yours?
Poor attention to detail... it's hard to work with people like that.
And these are not the people I want to hire to maintain my web servers.
Really? Ostensibly, you'd be paying them to maintain your web servers. Their personal web space would essentially be a hobby. Maybe, just maybe, they have other interests outside of their professional domain. I would rather hire someone who has a proven professional track record of maintaining web servers than someone who only has a pretty personal hobby-page. If all they do is run web servers, even as a hobby, they're more likely to burn out and they're less likely to have interests in common with clients.
I manage supply chains in my professional life. It would be pretty odd for a potential employers to expect me to do the same in my private life. In fact they might suspect that I was spending "work time" managing my other business. I mean, where do you draw the line? Does this potential employee's website have to have customers? Fail-over, backup, load-balancing, etc? Or will their personal site not be up to snuff?
And really, what does having a personal website have to do with running web servers?
That's okay though - it's a self-selecting process. You don't sound like the kind of person a happy, well-adjusted person wants to work for anyway.
Wow, this is kind of like when the unstoppble force meets the immovable object.
I'm sure the solution will be to have TSA officers carefully gird children with special lead loin cloths to cover their naughty bits before they are put through the scanner.
I missed the boat on buying stock in full-body scanner companies, but I may still be able to make a killing on the lead bathing suit manufacturers.
Take other classes, like Econ 101. Get a broad education, and with real life applicability.
Plus the chicks are hotter
If you want the hottest chicks, you really need to take classes in the education department, like theory of development. If you take elementary ed classes, you'll actually get college credit for finger painting and making paper mache masks. And be in classes with hot girls.
I'd also recommend taking a look at Ars Digita University's old Computer Science materials at http://aduni.org/.
The discrete math course has nice videos of the lectures, so it could be a nice way to augment whatever course someone takes live. Plus there are additional problems (some with answers). And the book for the course, being 10 years old, can be picked up for under $10.
http://www.aduni.org/courses/discrete/
You also saw Computer Science coming out of math departments as well. Where I was going to school in the 70s, Computer Science was under math, but Computer Engineering was being built in the Engineering department. There was certainly some overlap. My guess is you saw it coming out of whichever department had the most clout and desire to have it.
It doesn't even have to be anthropogenic climate change.
Any significant climate change, regardless of the source, has the potential to wreak havoc on the economy and that impacts national security. Food security is a large part of national security and when zones for growing key crops changes, we might not be able to respond fast enough. Changes in climate will also most likely effect availability of water. California has been in a drought for several years now. It's also a key food-producing region. A long-term change in precipitation patterns could devastate the agriculture there.
Higher sea temperatures will lead to more energetic hurricanes, which definitely will effect the gulf and south-eastern seaboard of the US. And of course rising sea levels will impact any of the cities near sea level and will probably lead to salinization of currently fresh-water marshes near the ocean.
Even if you deny the probability of anthropogenic impact on the climate, the "natural swings" in the climate can still have a large impact on the security of the nation. Therefore, it IS within the scope of the CIA's work to keep an eye on it.
And of course, this is just looking at the direct impacts on the US. These same climate-related problems will be global in nature and that will also have a destabilizing effect on governments around the world; both ones we like and ones we don't.
In short, Sen. Brasso is an idiot. Anything that can severely impact national security is clearly in the purview of the CIA.
The subway in Paris had tall narrow gates that would open (rather than a turnstyle). That worked really well and would keep all but the most aggressive from jumping over. They were at least 6 feet tall.
Sure, it would be inconvenient, but not as inconvenient as having the terminal emptied.
Most of their products are very low quality anyway and end up costing more in the long run.
Well, they are Chinese factories, but most often it's American/Western companies who are providing designs, specifying materials, and ordering products. The products low quality is not due to the Chinese - who can make things at any level of quality, but the American companies who set the bar as low as it is.
When your pair of Chinese-made Nike or Adidas shoes fall apart, it's because of the design and materials specification.
And why do the western companies do this? (specify cheap low quality products) Because that's what sells in America. Americans either don't want or can't afford quality. They flock to Walmart because they'd rather buy a cheap plastic piece of crap product rather than a durable quality product.
You allude to a situation I heard in a story once (and can't quickly find) that comes down to work boots. A poor man always has to buy the cheapest boots because that's all he can afford. A richer man can buy a good quality pair of boots, even though they cost much more. In the long run, however, the poor man will have ended up paying much more for boots because he has to keep buying replacements.
So we (Americans), end up buying so much cheap low-quality stuff not so much because it's Chinese, but because we vote with our dollars and keep buying it. We don't complain about the quality or demand better products, but instead run in herds to Walmart to get the $25 POS DVD player. And of course it's a vicious cycle... who can afford to stock and sell quality products when you don't have buyers to support your business? It's a "race to the bottom".
Dammit, by the circular firing-squad nature of this discussion, it's clearly a scheme hatched by The Left. Nobody can snatch defeat from the jaws of victory like the Democrats.
But LED lights flicker at 60Hz.
Do you see this with all LEDs? Or just some? My understanding is that LEDs use DC current to work (being a diode, the current only flows in one direction).
I've noticed differences between sets of Christmas LED lights and I assumed the flickering was from using a cheaper half-wave rectifier to convert the AC wall current to a DC signal for the LEDs. Using a half-wave rectifier would mean they were only on during half the AC cycle and off during the other half (this only needs 2 diodes). With a full wave, you need 4 diodes, but you have the lights on through the entire AC cycle, except for the moments where the wave is at 0 voltage. Even that can be fixed using coils and capacitors to smooth the signal out.
However, I would think that LEDs powered from a DC source, such as a car battery, would not exhibit the flickering.
It's an interesting problem.
Red-green colorblindness should not affect the ability of a person to correctly observe a traffic light.
Under ideal conditions, you're correct. (But this whole article is about non-ideal conditions)
I have some color blindness and I can describe the problem I have. When it's raining and at night, it's difficult for me to tell a green light (non LED) from a nearby street illumination light (from a distance). I know that sounds crazy. Because it's dark, it's hard to see the rectangular enclosure, so I can't tell by the green-light's position. Only after it's changed to yellow then red can I tell which light was the illumination light and which was the green light.
And I can't just assume that lack of a yellow or red means I have the green, because it might be burned out.
The new LED lights use a different color of green that has a higher blue component that makes them completely obvious. Plus the LED lights are more intense than the other lights. This may be due to the light from an LED being a smaller set of frequencies (or a single one?) compared to a filtered incandescent, though I really don't know much about the physics of LEDs.
So, I expect it was mentioned in this context because when it's dark it's harder to tell the position of the green light against the dark enclosure, especially when there are nearby white lights. And the blue-green used makes them easier to see. At least that's my experience.
It is one thing to update tech if it gives significant improvement in functionality, but, just doing it to be fashionably 'green' is not the way to do IMHO.
From the traffic manuals I've helped write, the LED traffic lights do indeed offer significantly improved functionality over incandescent lights in ways that are not related to "being green".
Actually, the "green" is a bluish color of green that makes it easier for people with color deficiency to tell from nearby white street lights (this is huge, being somewhat color blind myself - suppose it's raining at night and there are street lights near the stop light. For me, it's sometimes difficult to distinguish the green light from the nearby street light; only when it turns yellow and red can I tell which one belongs to the stop light. With the new ones, I have no problem at all.)
They're also made up of many LED elements per "light" so that when one inevitably burns out, most of the light still functions before a replacement can be done (say one of the green LEDs burns out - you still have several green LEDs working). With incandescent, when you lose red, you lose it completely. This improves safety for drivers and allows more flexibility in scheduling the work crews to replace the lights.
The LED lights are also brighter and more intense than the incandescent lights, making them more visible from farther way and in a wider range of ambient light conditions. (The incandescent lights don't do very well when the sun is directly behind you as you face a light - I think part of this is that the incandescent lights have a reflector behind the bulb, like a flashlight does - so the sunlight enters the lens from the front and then reflects back out. The LEDs don't have this reflector around the bulb).
Plus, the LED lights last significantly longer than the incandescent lights. You save money on the labor of replacing them - as well as reducing the safety risks to the work crews who have to go work in the street.
Of course, every new technology has unanticipated side effects, and the inability of the LED lights to melt off snow is one of them. But really, that's just an engineering problem that several people here have already suggested good solutions for.
In a similar vain, when I worked as a sysadmin at a university, we had a computer lab with 30 computers and we had the heat (old water pipes) permanently turned off because the monitors gave off enough heat to keep the room comfortable, even in winter. After we switched to LCD monitors, students started complaining that the lab was always too cold and we had to have maintenance come in and bring the heat back online. Likewise, an unintended consequence of a newer technology.
I don't think the terrorist recruiters are specifically seeking out Engineering students.
Based on my experience working in a University (and attending a couple) it seems to me that students who get sent abroad from Islamic countries study Engineering because it's a particularly useful degree back home. Many of these countries are underdeveloped and bringing back good engineering skills is a way to work towards correcting that. You just don't see as many students from the developing world here in the US getting degrees in art, English, or the social sciences.
Now, I if I were an Islamic terrorist recruiter, I'd most interested in finding people who had lived in the target country and could move around comfortably there. But they'd also need to be people who were grounded in Islam and hopefully susceptible to a more fundamentalist point of view. Young people tend to be more "flexible" in their theology than older people. So, who do I look for? Students from my own country who have been or are currently studying abroad and most of them are going to be Engineers. Plus these students have the added benefit of having already gone through the visa process and will probably much easier to get back into the target country.
I really don't think the recruiters and leaders are looking specifically for highly trained engineers so they can be expended on the front-line. If Engineers are actually valued for their technical skills, planning capability, etc, I'd use them for designing IEDs and planning operations. Considering the failures and apparent incompetence so far, maybe they are using the "bottom of the barrel" for the actual operations, since they have the qualifications to reach the target country but are not so capable in an Engineering capacity.
and the beating each other over the head with teams of lawyers!
Now, if only they'd start using trebuchets to launch lawyers at each other. I'd buy tickets to watch that.
I have been working IT for 20 years now and have ruined many nice silk ties on rough server cases. Switched to "cheap ties" but they still add up.
Your company should be picking up the cost of those ties. If they require you wear them and they are made unserviceable by the work you are required to do, then it's their responsibility. Heck, even the army, which is generally a crappy employer, will replace your stuff when it gets messed up at work.
There's actually an interesting Agent-Based Simulation system based (loosely) on Logo called NetLogo (http://ccl.northwestern.edu/netlogo/). You can do basic Logo stuff, but it can actually do some very sophisticated modeling and the syntax is not very difficult.
Using syntax similar to Logo, you have program agents to sense their environment and then take action based on that. The concepts scale well to other platforms like the Lego Mindstorms.
It's not a traditional programming environment but as a beginner you'd still need to understand the idea of variables, objects, and conditional logic. Plus it's very visually oriented and has many examples that a kid can play with and tweak.