2. Convinence, things like being able to park a cart next to a teller and have all the items charged instantly.
See #1. I don't know any retailer that would abide by less than 99.999% accuracy. RFID does not meet this requirement at all.
If you think this is true, you need to check your receipts and count your change more frequently.
I've never seen a shop that manages 99% accuracy... the clerk fails to scan an item (doesn't notice it didn't beep), the item is in the database with the wrong price, the item scans twice, the item is missing entirely (so the clerk asks you to give them the price)...
Attacker buys RFID-tracked product at store. Attacker alters RFID-tracked product to allow for attack. Attacker returns the product to the store shelf and waits... Joe Sixpack checks out with infected product. Clerk scans product and infects store database. All prices for all products now set to $0.
... and even drinking to much water. That's actually been a problem for several years now at marathons, half-marathons and other road races. People tend to drink at every water station. That lowers their electrolytes to the point they require medical help. It's actually much more common now than people dehydrating during races.
I'm deeply suspicious of the idea of intellectual property as a source of economic growth.
If the U.S. were to dominate the world economy via intellectual property (but not in any other way), why would other countries continuing paying us for knowledge which once in the wild can be reproduced again and again at no cost?
Right now countries will respect our IP "ownership", but that's because they can't sell their products here if they don't. With the U.S. still the largest economy on the planet, you don't want to be shut out. However, once the rest of the world develops robust middle-class markets the cost of paying the US again and again for ideas is going to lose its appeal. Intellectual property (especially in the form of patents) is a "I got here first, so you can't do this without my permission" model. It's a fiction that only works as long as everyone playing agrees to believe in it (unlike, say, a rock, which is there whether you believe in it or not).
Energy does NOT need to be exerted to counteract a force: another force operating in an opposite direction with equal strength will do the job nicely.
Compression? If compression required the exertion of energy to counter it then everything in the Universe would collapse. What you are confusing is the act of compressing an object (which does typically generate heat) with an object existing in a STATE of compression (which is a state in which the forces compressing the object are in balance with those preventing further collapse).
It is TRUE that compressing an object so that it takes up less volume requires energy: work IS being done as the object is getting smaller. Once the volume stops changing (forces in balance), no work is being done and no energy is being consumed.
Your example of gravity is likewise wrong: a counteracting FORCE produces stability, NOT the exertion of energy. Forces exist independently of work. This is the foundation for the entire concept of potential versus kinetic energy.
If you have not studied physics, I can see that this can be confusing because many of the terms are used loosely day-to-day, but in physics that is not the case. If you are truly interested, pick up a college level physics text meant as an introductory course for physics majors (don't get one of the "overviews" for non-majors). Better yet, pick up an undergraduate text in Newtonian Mechanics. The principles you will learn carry over into thermodynamics, so you should get a better understanding of exactly what I'm discussing. In case you haven't guessed by now, I have a degree in physics from UNC-Chapel Hill.:-)
UNC-Chapel Hill has over 27,000 students and began requiring laptops starting with the incoming class in 2000. It all works through the Carolina Computing Initiative: http://www.unc.edu/cci/ We even have IBM/Lenovo repair service right here on campus and 4-year warranties on the laptops. A Microsoft site license and IBM ImageUltra helps them maintain system images and covers software licenses.
I'm a OS X fan (Linux for servers), but I have to admit that UNC did a great job on making this work.
Something can float without work being done or energy being used. A FORCE has to exist, but that doesn't mean energy is being consumed or work is being done. A boat floats in water because the force exerted on the boat by the water it displaces counteracts the force of gravity trying to sink it. Zero work is done by a floating boat though forces are acting on it to keep it floating.
Sounds like me. I switched at the office, I switched at home. I switched my father-in-law. I switched my mom. I'm starting a side-business and will likely buy a pair of MacBooks for it as well.
No: we actually travel through time at slightly different rates all the, er, time. We just don't notice it because the effect is so small under normal conditions.
The passage of time varies with velocity and the presence of gravitation fields. You can actually measure the difference using atomic clocks. Both clocks will pass through the same points in time, but at different relative times. That is, when you bring the clocks back together you will find they have a discrepancy that is due to the difference in velocities and gravitational fields that they experienced while apart. This test has been done many times and the results are completely in agreement with General Relativity.
No. You misunderstand the twin paradox: the twin that journeys will age less than the twin that stays behind in the classic "paradox".
The two frames are not inertial frames since one twin accelerates during the experiment. While the result is no doubt peculiar, there actually is no paradox to resolve.
You can read all about it here: http://en.wikipedia.org/wiki/Twin_paradox
No, but it IS completely incorrect. It basically assumes that an 8 year old is 8/11 as intelligent as an 11 year old. I just can't believe in all the yammering I see with people blaming pop culture that I can't find a single post pointing out that the summary shows horrifically poor math skills.
Diebold is trying to interpret the statute to mean more than it says.
NC doesn't want to know who coded Windows or to get Windows source code: NC wants to see the software package that tracks and tallies the votes. Yes, you could try to stretch the meaning of the statute, but NC isn't trying to do that: Diebold is trying to in order to claim that compliance with the statute is impossible.
The real issue here is that Diebold doesn't want NC to see what's in Diebold's code. Makes it awfully suspect to me...
Like people have noted: it's Blizzard's world, so they get to make the rules and enforce the rules or not at their pleasure.
Now, Slashdot is Rob's world (notice that UID of "1" next to "CmdrTaco"?). If he wants to rant here about WoW or parking tickets or fuzz between his toes he has the absolute right to do so. It's not like you have to read everything that gets posted, and it's not like he posts any sort of personal gripe more than once in a blue moon.
Sometimes you just have to get it off your chest, and this is Rob's place to say whatever he pleases.
It doesn't matter in this case. The rays are still effectively parallel this far out. The distance from the Earth to the sun relative to the diameter of the sun makes the divergence of the rays trivial for the purposes of this problem.
A flat mirror has negligible dispersion when reflecting sunlight. Sunlight striking a small portion of the Earth's surface can be treated as truly parallel rays unless you are reflecting it to astronomical distances. That's why a mirror from a make-up compact makes such an effective signalling device: even at large distances it is still extremely bright. Dispersion of light sources is more aptly applied to point sources where the rays radiate outward in all directions. Far enough from a point source, however, the rays are effectively parallel over shorter distances.
The dispersion from the mirror would basically be due only to whatever deviations from truly flat the mirror has.
Sunlight at the Earth's surface is about 1000 W/m^2. Flat mirrors all pointing to reflect the sun's light to a single area would basically produce an area of light equivalent in size to that of the mirrors with an intensity equal to the amount of sunlight on one mirror multiplied by the number of mirrors. For example, 300 square mirrors with an edge length of 0.5 meters would deliver approximately 75,000 W of power onto 0.5 x 0.5 meter area if correctly aligned.
If you have enough mirrors you can burn just about anything. Another example of "give me a lever long enough and I can move the world."
Disclaimer: I have a B.S. in Physics (UNC-Chapel Hill), so I have a vested interest in the laws of physics and my opinions may therefore be non-neutral. Also, I have something like the flu, so you should check my math...:-)
I believe you CAN go out there and find the work you want and can make a living at it IF you want badly enough to do the very hard work of getting there.
Your shelf-stackers that want to be architects can't just quit to become an architect. They have to pay the bills while working to fulfill their dreams. That means stacking shelves while going to school -- possibly school during the day and stacking in the evenings. It may mean eating Ramen noodles twice a day and taking the bus so they don't have to own a car. It means working twice as hard NOW to realize a dream LATER.
Few people have that kind of resolve and discipline.
Your mechanic that wants to be a painter? Can he make a living with his paintings? If not, he'll stay a mechanic and paint on the weekends if he loves to paint.
The electrician that wants to be a musician? Do you play an instrument? I play a little guitar: it takes every bit as much work to learn to play well as it took me to get my degree in physics.
After I graduated from college I took a job doing research under contract with the EPA. It payed well. The hours were comfortable. The security was high...... but I didn't like the work. I decided I wanted to work with computers (back around 1990). I grabbed a big, thick book on "Upgrading and Maintaining PC's" and learned as much as I could. Studied. CRAMMED.
Then I found a company looking for an entry-level tech offering a MUCH lower salary than I had with my research position -- I dropped to $24,000/year. I spent 18 months in a hellish job, but it gave me the skills and experience to move on to a better position.
In other words, I was willing to pay the price to move on to something better -- and I wasn't in a bad position to begin with!
I'm now a senior systems developer and administrator implementing a HIPAA-compliant network of my own design using open source solutions in a research institute dedicated to child development studies.
Getting here was HARD. Leaving my stable research job was SCARY.
Shelf-stockers, factory workers, bartenders: there are some people are quitting those jobs all the time to follow a dream. However, MOST people will take the security of their current, unloved job over the scary leap. Most would rather have a beer after work with friends than go home to hit the books or practice their music, or hone their craft.
Most people can get up and chase their dream, but it often comes at a price they are not willing to pay.
I'll just second lgw's numbers (at least the second one). I ran the calculations myself and got 180,000TW for total solar power striking the Earth. The albedo number might be a bit high, though.
Catholics that didn't get to go to Catholic schools ended up "disconnected" and therefore left the Catholic Church to join the evangelicals???
I find this line of reasoning goes well outside the limits of credibility. This is the first time I've ever seen this line of reasoning:
Evangelical atheists --> end of most Catholic schools --> conversion of "disconnected" Catholics to evangelicals in Megachurches.
You do realize that Catholicism is strongest in the northeast, but the megachurches are largest in places such Houston and Colorado Springs, right? Does this mean Catholics not only converted to being Evangelicals, but also moved away to do so?
I would suggest (unless you have some good sources to support your theory) that you think through this a little more.
Why is it whenever we see someone claim that evolution is soundly refuted by the fossil record and genetic analysis that we never see any reputable scientific source quoted?
On the contrary, the evidence is overwhelming and numerous respected sites can teach you about the evidence:
National Academy of Science: http://books.nap.edu/html/creationism/
Berkeley (resource for teachers): http://evolution.berkeley.edu/
I can find no reputable scientific organization that expresses doubts about the soundness of evolution. Yes, there are details about how certain changes took place within the framework of evolution, but there is no true debate in scientific societies concerned with associated fields (anthropology, biology, paleontology, etc) as to the overwhelming evidence in support of evolution.
If anyone wants to challenge evolution as a solid theory, I would ask that they PLEASE back it up with credible, reputable sources.
Not as significantly as you might think. CPI is regularly adjusted to make it as accurate as possible and was substantially altered back in 1995 to reduce bias in the CPI. The Boskin Report was the basis for these changes.
The shuttle should have been a step towards true spaceplanes. It wasn't efficient, but it explored our prospects for fully reusable launch vehicles.
The next step was to be real spaceplanes. After that we could begin talking about things like commercial spaceliners, orbiting manufacturing facilities and all the other sci-fi dreams of my childhood.
Instead, we're finding that we can't (or won't: $$$) build on what we learned with the shuttle to create spaceplanes, so we're going back to rockets.
We went from sails to steam-driven paddleboats (which worked poorly) to propeller-driven steamships (which worked really well). The shuttle program is equivalent to saying "These paddleboats just have no future. Let's go back to sails."
Same thing happened to me. I got my 5 points yesterday morning -- they vanished before noon. Something's amiss.
More on topic -- the funny thing about Cisco's role in all this is that I tend to trust companies that come forward and speak out forcefully in admitting a problem with a product. It makes me confident that they will fix it and fix it right.
By going after the guy that dared discuss the problem I've lost trust in Cisco. If they didn't want this discussed it makes me wonder if they might have a bunch of other problems that they've succeeded in keeping hidden. The harder they go after him, the less trust I have in their products.
Slashdot Mirror
2. Convinence, things like being able to park a cart next to a teller and have all the items charged instantly.
See #1. I don't know any retailer that would abide by less than 99.999% accuracy. RFID does not meet this requirement at all.
If you think this is true, you need to check your receipts and count your change more frequently.
I've never seen a shop that manages 99% accuracy... the clerk fails to scan an item (doesn't notice it didn't beep), the item is in the database with the wrong price, the item scans twice, the item is missing entirely (so the clerk asks you to give them the price)...
99.999%???
Would they have to be nearby?
I see a real threat for anonymous attacks:
Attacker buys RFID-tracked product at store.
Attacker alters RFID-tracked product to allow for attack.
Attacker returns the product to the store shelf and waits...
Joe Sixpack checks out with infected product.
Clerk scans product and infects store database.
All prices for all products now set to $0.
... and even drinking to much water. That's actually been a problem for several years now at marathons, half-marathons and other road races. People tend to drink at every water station. That lowers their electrolytes to the point they require medical help. It's actually much more common now than people dehydrating during races.
I'm deeply suspicious of the idea of intellectual property as a source of economic growth.
If the U.S. were to dominate the world economy via intellectual property (but not in any other way), why would other countries continuing paying us for knowledge which once in the wild can be reproduced again and again at no cost?
Right now countries will respect our IP "ownership", but that's because they can't sell their products here if they don't. With the U.S. still the largest economy on the planet, you don't want to be shut out. However, once the rest of the world develops robust middle-class markets the cost of paying the US again and again for ideas is going to lose its appeal. Intellectual property (especially in the form of patents) is a "I got here first, so you can't do this without my permission" model. It's a fiction that only works as long as everyone playing agrees to believe in it (unlike, say, a rock, which is there whether you believe in it or not).
No, you're mistaken.
:-)
Energy does NOT need to be exerted to counteract a force: another force operating in an opposite direction with equal strength will do the job nicely.
Compression? If compression required the exertion of energy to counter it then everything in the Universe would collapse. What you are confusing is the act of compressing an object (which does typically generate heat) with an object existing in a STATE of compression (which is a state in which the forces compressing the object are in balance with those preventing further collapse).
It is TRUE that compressing an object so that it takes up less volume requires energy: work IS being done as the object is getting smaller. Once the volume stops changing (forces in balance), no work is being done and no energy is being consumed.
Your example of gravity is likewise wrong: a counteracting FORCE produces stability, NOT the exertion of energy. Forces exist independently of work. This is the foundation for the entire concept of potential versus kinetic energy.
If you have not studied physics, I can see that this can be confusing because many of the terms are used loosely day-to-day, but in physics that is not the case. If you are truly interested, pick up a college level physics text meant as an introductory course for physics majors (don't get one of the "overviews" for non-majors). Better yet, pick up an undergraduate text in Newtonian Mechanics. The principles you will learn carry over into thermodynamics, so you should get a better understanding of exactly what I'm discussing. In case you haven't guessed by now, I have a degree in physics from UNC-Chapel Hill.
1000?
UNC-Chapel Hill has over 27,000 students and began requiring laptops starting with the incoming class in 2000. It all works through the Carolina Computing Initiative: http://www.unc.edu/cci/ We even have IBM/Lenovo repair service right here on campus and 4-year warranties on the laptops. A Microsoft site license and IBM ImageUltra helps them maintain system images and covers software licenses.
I'm a OS X fan (Linux for servers), but I have to admit that UNC did a great job on making this work.
Work = (Force)(Displacement)
Something can float without work being done or energy being used. A FORCE has to exist, but that doesn't mean energy is being consumed or work is being done. A boat floats in water because the force exerted on the boat by the water it displaces counteracts the force of gravity trying to sink it. Zero work is done by a floating boat though forces are acting on it to keep it floating.
Sounds like me. I switched at the office, I switched at home. I switched my father-in-law. I switched my mom. I'm starting a side-business and will likely buy a pair of MacBooks for it as well.
No: we actually travel through time at slightly different rates all the, er, time. We just don't notice it because the effect is so small under normal conditions.
The passage of time varies with velocity and the presence of gravitation fields. You can actually measure the difference using atomic clocks. Both clocks will pass through the same points in time, but at different relative times. That is, when you bring the clocks back together you will find they have a discrepancy that is due to the difference in velocities and gravitational fields that they experienced while apart. This test has been done many times and the results are completely in agreement with General Relativity.
No. You misunderstand the twin paradox: the twin that journeys will age less than the twin that stays behind in the classic "paradox".
The two frames are not inertial frames since one twin accelerates during the experiment. While the result is no doubt peculiar, there actually is no paradox to resolve.
You can read all about it here:
http://en.wikipedia.org/wiki/Twin_paradox
No, but it IS completely incorrect. It basically assumes that an 8 year old is 8/11 as intelligent as an 11 year old. I just can't believe in all the yammering I see with people blaming pop culture that I can't find a single post pointing out that the summary shows horrifically poor math skills.
Diebold is trying to interpret the statute to mean more than it says.
NC doesn't want to know who coded Windows or to get Windows source code: NC wants to see the software package that tracks and tallies the votes. Yes, you could try to stretch the meaning of the statute, but NC isn't trying to do that: Diebold is trying to in order to claim that compliance with the statute is impossible.
The real issue here is that Diebold doesn't want NC to see what's in Diebold's code. Makes it awfully suspect to me...
Like people have noted: it's Blizzard's world, so they get to make the rules and enforce the rules or not at their pleasure.
Now, Slashdot is Rob's world (notice that UID of "1" next to "CmdrTaco"?). If he wants to rant here about WoW or parking tickets or fuzz between his toes he has the absolute right to do so. It's not like you have to read everything that gets posted, and it's not like he posts any sort of personal gripe more than once in a blue moon.
Sometimes you just have to get it off your chest, and this is Rob's place to say whatever he pleases.
It doesn't matter in this case. The rays are still effectively parallel this far out. The distance from the Earth to the sun relative to the diameter of the sun makes the divergence of the rays trivial for the purposes of this problem.
A flat mirror has negligible dispersion when reflecting sunlight. Sunlight striking a small portion of the Earth's surface can be treated as truly parallel rays unless you are reflecting it to astronomical distances. That's why a mirror from a make-up compact makes such an effective signalling device: even at large distances it is still extremely bright. Dispersion of light sources is more aptly applied to point sources where the rays radiate outward in all directions. Far enough from a point source, however, the rays are effectively parallel over shorter distances.
:-)
The dispersion from the mirror would basically be due only to whatever deviations from truly flat the mirror has.
Sunlight at the Earth's surface is about 1000 W/m^2. Flat mirrors all pointing to reflect the sun's light to a single area would basically produce an area of light equivalent in size to that of the mirrors with an intensity equal to the amount of sunlight on one mirror multiplied by the number of mirrors. For example, 300 square mirrors with an edge length of 0.5 meters would deliver approximately 75,000 W of power onto 0.5 x 0.5 meter area if correctly aligned.
If you have enough mirrors you can burn just about anything. Another example of "give me a lever long enough and I can move the world."
Disclaimer: I have a B.S. in Physics (UNC-Chapel Hill), so I have a vested interest in the laws of physics and my opinions may therefore be non-neutral. Also, I have something like the flu, so you should check my math...
Nat Geo DOES have ads -- they just limit them to a few in the front and maybe the back cover.
Best. Parody. Ever.
Bravo! Bravo!
No no no no no...
... but I didn't like the work. I decided I wanted to work with computers (back around 1990). I grabbed a big, thick book on "Upgrading and Maintaining PC's" and learned as much as I could. Studied. CRAMMED.
I believe you CAN go out there and find the work you want and can make a living at it IF you want badly enough to do the very hard work of getting there.
Your shelf-stackers that want to be architects can't just quit to become an architect. They have to pay the bills while working to fulfill their dreams. That means stacking shelves while going to school -- possibly school during the day and stacking in the evenings. It may mean eating Ramen noodles twice a day and taking the bus so they don't have to own a car. It means working twice as hard NOW to realize a dream LATER.
Few people have that kind of resolve and discipline.
Your mechanic that wants to be a painter? Can he make a living with his paintings? If not, he'll stay a mechanic and paint on the weekends if he loves to paint.
The electrician that wants to be a musician? Do you play an instrument? I play a little guitar: it takes every bit as much work to learn to play well as it took me to get my degree in physics.
After I graduated from college I took a job doing research under contract with the EPA. It payed well. The hours were comfortable. The security was high...
Then I found a company looking for an entry-level tech offering a MUCH lower salary than I had with my research position -- I dropped to $24,000/year. I spent 18 months in a hellish job, but it gave me the skills and experience to move on to a better position.
In other words, I was willing to pay the price to move on to something better -- and I wasn't in a bad position to begin with!
I'm now a senior systems developer and administrator implementing a HIPAA-compliant network of my own design using open source solutions in a research institute dedicated to child development studies.
Getting here was HARD. Leaving my stable research job was SCARY.
Shelf-stockers, factory workers, bartenders: there are some people are quitting those jobs all the time to follow a dream. However, MOST people will take the security of their current, unloved job over the scary leap. Most would rather have a beer after work with friends than go home to hit the books or practice their music, or hone their craft.
Most people can get up and chase their dream, but it often comes at a price they are not willing to pay.
Do you upgrade your computer every time a new processor comes out????
Bad analogy, there, you're posting on Slashdot after all...
I'll just second lgw's numbers (at least the second one). I ran the calculations myself and got 180,000TW for total solar power striking the Earth. The albedo number might be a bit high, though.
c hap2/Albedo.html
http://profhorn.aos.wisc.edu/wxwise/AckermanKnox/
WHAT?
Catholics that didn't get to go to Catholic schools ended up "disconnected" and therefore left the Catholic Church to join the evangelicals???
I find this line of reasoning goes well outside the limits of credibility. This is the first time I've ever seen this line of reasoning:
Evangelical atheists --> end of most Catholic schools --> conversion of "disconnected" Catholics to evangelicals in Megachurches.
You do realize that Catholicism is strongest in the northeast, but the megachurches are largest in places such Houston and Colorado Springs, right? Does this mean Catholics not only converted to being Evangelicals, but also moved away to do so?
I would suggest (unless you have some good sources to support your theory) that you think through this a little more.
Why is it whenever we see someone claim that evolution is soundly refuted by the fossil record and genetic analysis that we never see any reputable scientific source quoted?
On the contrary, the evidence is overwhelming and numerous respected sites can teach you about the evidence:
National Academy of Science:
http://books.nap.edu/html/creationism/
Berkeley (resource for teachers):
http://evolution.berkeley.edu/
I can find no reputable scientific organization that expresses doubts about the soundness of evolution. Yes, there are details about how certain changes took place within the framework of evolution, but there is no true debate in scientific societies concerned with associated fields (anthropology, biology, paleontology, etc) as to the overwhelming evidence in support of evolution.
If anyone wants to challenge evolution as a solid theory, I would ask that they PLEASE back it up with credible, reputable sources.
Not as significantly as you might think. CPI is regularly adjusted to make it as accurate as possible and was substantially altered back in 1995 to reduce bias in the CPI. The Boskin Report was the basis for these changes.
Wikipedia also features a good article explaining the CPI and its limitations.
To me, that's the problem.
The shuttle should have been a step towards true spaceplanes. It wasn't efficient, but it explored our prospects for fully reusable launch vehicles.
The next step was to be real spaceplanes. After that we could begin talking about things like commercial spaceliners, orbiting manufacturing facilities and all the other sci-fi dreams of my childhood.
Instead, we're finding that we can't (or won't: $$$) build on what we learned with the shuttle to create spaceplanes, so we're going back to rockets.
We went from sails to steam-driven paddleboats (which worked poorly) to propeller-driven steamships (which worked really well). The shuttle program is equivalent to saying "These paddleboats just have no future. Let's go back to sails."
Same thing happened to me. I got my 5 points yesterday morning -- they vanished before noon. Something's amiss.
More on topic -- the funny thing about Cisco's role in all this is that I tend to trust companies that come forward and speak out forcefully in admitting a problem with a product. It makes me confident that they will fix it and fix it right.
By going after the guy that dared discuss the problem I've lost trust in Cisco. If they didn't want this discussed it makes me wonder if they might have a bunch of other problems that they've succeeded in keeping hidden. The harder they go after him, the less trust I have in their products.