If you don't mind going a little DIY, there is the Ubiquiti RouterStation Pro. It's a board with four GigE ports and three mini-PCI slots for wireless cards, and comes loaded with Open WRT. Look around online and you should be able to find a few places selling it with a simple case, power pack, and a wireless card for ~$150 or less. Note, I haven't used it, so I can't speak from experience. It's on my wishlist though:)
I haven't used it either, but I've used some other Ubiquiti products and have been very pleased with their hardware and software. Very stable and well developed.
Get a cheap intel atom with dual intel nics and install pfsense 2.0 and away you go. Most Atoms are under 18 or so watts.
I wish I had mod points to mark it as insightful. pfSense will give you all of the features you will ever want, and you'll never have to worry about it locking up under some sort of load. I use an old Pentium III (old one that was just laying around) that pulls just a little power, and is orders of magnitude more powerful than any consumer router you could get.
You can get a PCIe wireless card to plug into your board, but I just turn off DHCP on my D-Link N router and plug into the switch portion of it. The D-Link would lock up all the time as a router, but acting as a switch/access point it's just fine.
The problem comes when that non-zero probability is less than the chance your child will get sick and/or die from that disease from a largely vaccinated population? From a purely self-interested and logical perspective, if just about everybody is vaccinated from a disease and that disease is no longer prevalent in the population as a whole, the probability of a child dying from the vaccination is actually higher than if the child was exposed to the vaccination. In this perspective, those who refuse vaccinations really are looking after the well being of their own children and in effect depending on the rest of the society to be sheep and following what everybody else is doing.
Specifically, those who demean and ridicule those who refuse vaccinations simply are showing almost as much ignorance as some of those who refuse vaccinations. I am proclaiming here that there are valid reasons to refuse to vaccinate your children, even though in my case I have (mostly) vaccinated my children against most common childhood illnesses. My rationale is that both I and my children are in contact with enough people that the probability at the moment of contracting these diseases if they weren't vaccinated is higher and the potential for their deaths, in my view and estimation, than if they weren't vaccinated. I don't claim to have 100% knowledge on this topic and I certainly don't think it is my job to make that sort of calculation for somebody else in regards to their own children. I certainly don't think it is the role of the government to force at gunpoint the vaccinations of children.
Me thinks you missed a comment in there. Yes, there can be reasons, but most people couldn't possibly know them. Herd immunity is the result of a cooperative effort where everyone takes some small risk for a very large group gain. Each person that doesn't get a vaccine increases the risk to everyone else. They are essentially saying, "I will avoid 10 units of risk in return for a thousand other people receiving an extra 1 unit of risk."
There are certainly legitimate reasons not to get a vaccine (my wife and mother in law share a vaccine allergy, so we won't be giving it to my infant son until the formula changes). But the truth is that MOST of the time when people don't vaccinate, even if it is because the individual risk from the vaccine is greater than the risk of the disease, they are being selfish and wrong.
I've been thinking about becoming a paying customer, so I'm interested in this. Is it an issue with the number of files, the total size of all files, or the size of the largest file? And do you know what the limit is?
In my office, we're heavy users of laptops because people take them to meetings, and because people want to be able to get real work done from home, and you can only VPN in with a corporate device. We're currently looking into Citrix to let our users access whatever devices they want from home. I suspect at that point most people will switch to desktops with a few tablets floating around to access stuff in meetings. A few power users need to be able to type substantial amounts in remote locations, but I suspect those will be few and far between.
The current highest capacity wind turbines are 7.6 MW. I haven't been able to find figures on the area proposed for the collector area of this tower, but it is possible that 30-50 simpler and proven wind turbines or 1 to 5 concentrated solar units might be able to replace this tower.
Wind turbines work in a very limited number of regions. They would almost certainly be a complete failure here.
A solar concentrator would undoubtedly be more efficient per km^2, but that isn't really the point. It's worth investing in several versions of different technologies to see how well each scales, and how well each works out in the long run. Efficient solar concentrators are far more complex and have more moving parts than this system. The both cost the same initially for about the same power, while this tower takes more land area. But if it turns out that this tower lasts for 50 years with minimal maintenance, then it would be an easy win. There are many places where having low maintenance easily trumps land usage.
There are also a number of experiments that having this type of tower around would make simple, which would be otherwise impossible. For instance, what would be the climate effect of letting massive amounts of water evaporate below and be released at 2600 feet? There are a lot of interesting things you could test. Would this tower indicate an even taller tower being practical?
So basically you want to create a Meta-Power Plant. While I don't think they need the resonance aspect to it they could certainly add turbines to the outside to capture passing winds (they're doing this on some modern towers), solar underneath (instead of having a black painted floor even), and adding in geothermal (if feasible at that site) would be icing on the cake.
Solar cell power efficiency tends to drop off at temperature increases. Of course, if you can get them for cheap enough then it probably doesn't matter. I'd guess that building to carry the extra weight and stress of external turbines would not be a cost effective move. The goal is essentially a giant chimney, so anything that changes that is going to drive up costs quite a bit.
I think you don't know what you're talking about much less being confused. Emissivity defines reflectivity, as in an objects emissivity rate is it's effective reflection rate for a particular wavelength at a particular temperature, etc. etc.
Also, the solar spectrum is not most intense at the visible part. To quote Wikipedia, who has a source.
"Sunlight at zenith provides an irradiance of just over 1 kilowatt per square meter at sea level. Of this energy, 527 watts is infrared radiation, 445 watts is visible light, and 32 watts is ultraviolet radiation.[2]"
The GP's point still stands for two very important reasons, most objects emit radiation almost exclusively in the infrared and visible light is a significant source of energy. To demonstrate the importance of this, take these two situations:
Situation 1: You have a paint A which reflects 50% of visible and 50% of infrared light. Paint B reflects 90% of visible light, but only 40% of infrared. This is more or less the situation described by the original parent where the Krylon paint has higher infrared emissivity (lower reflectivity). From the numbers you provided, paint A would be absorbing 486 Watts (527*.50+445*.50) while paint B would be absorbing 320 Watts (527*.10+445*.60). So paint B would still absorb less energy, and it would dissipate the energy more quickly as infrared radiation, while paint B would be forced to conduct more of its energy into the underlying surface.
Situation 2: Taken to the extreme, paint C reflects 0% of visible light and 100% of infrared light. Paint D reflects 100% of visible light and 0% of infrared. Now paint D is consuming more energy than paint C, however it is simultaneously quickly dissipating most of that energy via infrared. Paint C however will probably burst into flames if its underlying surface is unable to absorb enough of the energy quickly enough.
These are both carefully crafted situations to show specifically that higher emissivity in the infrared CAN be just fine, and it's good to know that this is often not the case. The point was to clearly show the flaw in the OP's assertion that Krylon white paint having a higher emissivity in the infrared could somehow be the only fact to prove that it would be worse for covering a house.
Furthermore, and conveniently ignored, is the fact that above a certain latitude more energy is expended heating in the winter than cooling in the summer. New York City and Chicago are above that latitude, which is around 38-42 degrees on the East Coast depending on the year's average solar irradiance but varies widely across the country (because of airflow and humidity).
Or the fact that air conditioning was never a major concern for energy conservation, since the vast majority of energy used in buildings are to heat it, not cool it.
In very cold climates/seasons, the roofs are typically covered with snow, which negates the benefits of light absorbing roofs. Often you'll see snow melt just where the roofs are leaking heat, which is where you would would a roof with a very low emissivity in the infrared. And at those latitudes and times of the year, the amount of solar radiation available is not going to make much impact. Besides, heating energy statistics can be very misleading. For instance, the Mall of America in Minnesota runs their cooling system all year round due to the heat produced by lighting and human bodies.
Ummm...I don't have a black asphalt roof on my home in Mesa, AZ. I have clay tiles.
IIRC, one of the reasons that traditional clay tile roofs have been around so long, particularly in warm climates, is that there is a continuous flow of air between the tiles and the underlayment due to natural convection. The tiles may get quite hot, but the air flow keeps most of that heat from reaching the rest of the building.
This is true, but white tiles would still be far better for the environment. White tiles would reflect most of the heat/light back out into the atmosphere where a fair portion of it would end up making it back into space. Regular tiles help keep the house cool, but still heat up the surrounding air, causing a slight temperature increase for everyone. Of course, one house isn't going to make a difference, but the point was that if everyone did it, then the temperature of the entire area would drop by a few degrees.
(Note that I'm not suggesting reflecting all light for an area into space as we need that light for growing plants and such. But light that gets absorbed by roofs and streets end up being bad for everyone.)
Precisely. When I lecture, I am constantly engaging the people I'm talking to, not just checking to see if they're paying attention, but honestly asking their opinions about the problems I pose. And the problems I do pose tend to be more open-ended, with no one particular right or wrong answer. ("How would you change energy policy in America?" "Do you think recycling is a good idea?" "How do you try to convey ideas using technology?")
The Khan lectures appear to focused on quantifiable topics like mathematics where there are specific right and wrong answers. Declaring it a poor idea because it doesn't work for all types of learning is missing the point.
The students go home and watch lectures about specific math topics and answer sample questions. The teacher can see which students did well and poorly on different sample questions via charts and graphs on the website. The teacher can then assign students that did well to assist those that did poorly to better understand topics, and the teacher can provide more qualified and directed assistance where needed.
Honestly, the model seems pretty ideal for that topic. For a philosophy class, it wouldn't work nearly as well, but that's not where they're trying to use it.
I used to wonder why they never marketed it widely, but now I think I've guessed: because the MD music format was already out, they might have been afraid that allowing a direct attachment to a computer would enable people to rip their music and record copies on other discs. That's exactly the kind of thinking Sony has used when it's shot itself in the foot time and time again, the only difference being this was before everyone started making MP3s.
This. Sony screwed itself over when it got into the content production market. That division has effective killed every interesting technology they've come out with in the name of keeping their content safe. (Ironic considering that there probably isn't a single piece of content they own that can't be downloaded for free from the internet.)
Had they immediately made MD-data drives available and licensed the technology out to everyone, it would have easily become a standard. Instead the smaller capacity and more expensive Zip disks picked up popularity and then quickly faded due to poor capacity and reliability problems. MiniDiscs in the US were relegated to a niche market that they died in. The computer world would have been a very different place if Sony hadn't screwed themselves over with their own greed.
When I had to use the Notes client, it was pretty terrible, but that was back in 2003, and I don't recall the version. I've known several people in the past year that have had the client at their place of work, and it seems to be universally hated, although I don't know the versions. Even if the servers are of comparable quality, it seems that the overwhelming dislike for the client would make Lotus a thing to move away from.
If you're having virus/trojan issues, then try using an edge filter of some sort. A number of companies sell them, like the Barracuda Spam Filter. Drop whatever you get between the internet and your Exchange filter and you will likely never see a virus hit Exchange. You can get a transparent proxy product to do general web browsing. That's what I do and I haven't seen a virus issue on Exchange in many years (with thousands of users).
I'm baffled by the intense dislike of the Ribbon. I expected to hate it, but very quickly found it a great thing - probably one of the nicer changes that Office has seen in a long time.
Agreed. It was a little annoying in Office 2007 because some applications used it, and other didn't. Outlook 2007 didn't use it, but it was used when creating messages, which was just ridiculously inconsistent. Now that Office 2010 uses it consistently across the board, I find it better in many ways (although worse in a few). For most simple tasks, it exposes the available options better.
In my experience, most people that use it for a month or so have no complaints.
The sacrifice of resolution isn't really that big a concern. Consumer cameras have far more resolution than they need these days, as the almighty megapixel has been used as a marketing ploy even though increasing pixel density on the CCDs has led to lower image quality overall. My 10 year old 2Mpx Canon still takes better pictures than any of my wife's last 3 compact cameras (4, 5 and 8Mpx Nikon and Canons), especially in low light. I would go so far as to say it doesn't make sense to have go beyond much more than 4Mpx with lenses the size of compact cameras, as details will be lost due to lens quality long before the pixel count causes loss of detail.
I would beg to differ. Your 2 megapixel camera may produce higher quality pictures than your wife's compacts, but that likely has nothing to do with the relative resolutions. The dot pitch on decent CCDs is relatively small, so increasing the number of mega-"pixels" from 2 to 4 is going to have a negligible impact on the amount of light gathered. At best you're going to have increased resolution and sharpness that can be further used by improved processing chips. At worst you're going to reach a point where the difference in neighboring pixels is the result of noise, but will still average out the same as a lower resolution picture.
For two cameras with CMOS sensors of identical area, the biggest difference in image quality (assuming a resolution that is 'good enough' for the application) is going to be dependent on three things. The size of the lens, the quality of the lens, and the quality of the processing chip. The difference with the size of the lens is especially important the lower the environment lighting. In high light situations the lens and processing quality become more important.
If you have a large enough CMOS sensor and lens, a higher resolution camera will absolutely stomp on a lower resolution. Of course, if you're not doing any post processing and you're just displaying it on your phone, it's not going to matter.
On their website, the sample photos from their drone are basically straight down. That would severely limit the quality of the imagery on vertical walls. I'm curious why they don't angle the camera at, say, 45*. That should allow good coverage of roofs and walls.
While Firewire was undeniably a more capable and faster standard than USB2, the real reason for the difference in speeds was the quality of the controllers that were used. Had USB controllers been as high quality as Firewire controllers, very few people would have seen a difference.
Because of the high number of controllers in use, there is a lot of motivation to design more low cost controller chips. The result is that some companies will produce a barely functional USB controller at an incredibly low price. When other companies are putting together a system of some sort, saving a few pennies by getting the cheapest controller seems to make a lot of sense in savings when you talking about millions of widgets with the controllers.
In truth, the vast majority of devices didn't need a fast USB controller from a consumer perspective. There will be little difference in the speed of your keyboard, mouse, or phone sync. The end result is that people stop making more capable/expensive controllers because no one is buying them. USB quickly lost quality due to being such a commodity.
The opposite happened with Firewire. Firewire controllers were more complex, and so were just used in devices that really required the higher speeds. These were almost exclusively higher costing luxury items, where spending a few more cents for a better quality controller made sense. While there were poor quality Firewire controllers, there were still many high quality controllers being made and used because they were useful and there was a large enough market.
I'll throw in another comment in support of pfsense. It'll install on any old PC, and with that PC it will be able to handle far more connections than you'd ever be able to throw at it, while providing QoS and per system bandwidth usage. It also supports plugins so will do all sorts of other features as add-ons (like transparent caching). I have a fancy QoS wireless router that I paid >$100, and I ended up turning off all of the features to use it as an access point behind pfsense.
You never realize it until you try, but an 8 year old PC is orders of magnitude more powerful than any consumer router. The total electrical usage for me from this is ~$30/year, which I'm okay with because of the extra ability. Eventually I'll get an Atom system and cut that in half or to a third.
Regardless of the hashing algorithm, there exists a possibility of a collision.
For any modern cryptographic hashing algorithm, the only possibility of a collision is to create one on purpose, and for modern ones there haven't been methods invented to do this. IE, it's impossible as long as they routinely update their hashing algorithm (which is easy as they can produce new hashes of the files they have, and force a minimum client version for new files. When you have as many possible combinations as there are atoms in the universe, you're more likely to win every lottery for a year than to have an accidental collision.
MD5 hasn't been secure for a few years, but it relatively ancient, being created in 1991. SHA-512 has no known vulnerabilities, and a new candidate for SHA-3 will soon be chosen. Heck, they could hedge their bets and use two different hashers to in case one is ever broken.
The only real danger is if you already knew the hash of a file, you could retrieve it. Of course, the
Yeah, really heavy wheels means you lose a lot of energy for every bump you go over, having to move all of that mass up/down.
I remember in the early 90's reading a Popular Mechanics article about a (Ford?) car being developed that would use a small electric motor at each wheel, which would allow them to precisely control the speed and power of each wheel independently. The power was provided by a regular combustion engine hooked to a generator. The motor was detached from the wheel by a single axle with a universal joint at each end, allowing for a full range of motion for the wheel without the weight of the motor interfering. It looked like the energy losses would have been relatively low, so I was excited to see where it went. Of course, there was zero news about any sort of hybrid system for a decade (Ford was even longer) and none of them have anything like that design, so there were probably fundamental issues with it. I'm not really sure what they would be.
There are a lot of things that sound like great ideas, but have serious issues with implementing that you would never think of until you try.
Why bother with transmissions, crankshafts, axels, and so on? Just extra weight to haul around. Hubless eletric motors on all wheels.
The added weight makes them horribly inefficient for anything except very smooth streets. Super heavy wheels tend to be a bad thing. This concept has worked well for some things, such as city buses where the city has well paved streets.
Smaller engines like that can be ideal for running in series (either electrically or mechanically). If you have a battery pack and a few engines (they say the engines are light), then you would be able to keep one engine on for cruising, and power up other engines if you need to charge the batteries or pull a boat up hill.
Sometimes I'm a bit biased towards OSS stuff, samba in particular. For me, it's a 5 minute operation to get samba up and running, joined to an AD domain and get shares going.
I'm something of an idealist, and I really hope for the OSS versions of software in the long run. That said, even if you can get Samba to work, don't do it. Once you leave the company, what assurances do you have that anyone will have a clue what to do when something breaks?
I work at a company that had large parts of its infrastructure custom built to solve the companies unique issues, by a bunch of really brilliant people; really brilliant people who are no longer there. We are now slowly working to replace all of those pieces with well understood industry standard software packages that will be easy to upgrade or replace in the future. They may not be the perfect fit, but who cares. Over time the needs of the business change, and that perfect fit becomes a terrible fit, while the decent fit stays decent (or has a well understood migration path). And it's a lot easier to find an admin to take it over.
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If you don't mind going a little DIY, there is the Ubiquiti RouterStation Pro. It's a board with four GigE ports and three mini-PCI slots for wireless cards, and comes loaded with Open WRT. Look around online and you should be able to find a few places selling it with a simple case, power pack, and a wireless card for ~$150 or less. Note, I haven't used it, so I can't speak from experience. It's on my wishlist though :)
I haven't used it either, but I've used some other Ubiquiti products and have been very pleased with their hardware and software. Very stable and well developed.
Get a cheap intel atom with dual intel nics and install pfsense 2.0 and away you go. Most Atoms are under 18 or so watts.
I wish I had mod points to mark it as insightful. pfSense will give you all of the features you will ever want, and you'll never have to worry about it locking up under some sort of load. I use an old Pentium III (old one that was just laying around) that pulls just a little power, and is orders of magnitude more powerful than any consumer router you could get.
You can get a PCIe wireless card to plug into your board, but I just turn off DHCP on my D-Link N router and plug into the switch portion of it. The D-Link would lock up all the time as a router, but acting as a switch/access point it's just fine.
The problem comes when that non-zero probability is less than the chance your child will get sick and/or die from that disease from a largely vaccinated population? From a purely self-interested and logical perspective, if just about everybody is vaccinated from a disease and that disease is no longer prevalent in the population as a whole, the probability of a child dying from the vaccination is actually higher than if the child was exposed to the vaccination. In this perspective, those who refuse vaccinations really are looking after the well being of their own children and in effect depending on the rest of the society to be sheep and following what everybody else is doing.
Specifically, those who demean and ridicule those who refuse vaccinations simply are showing almost as much ignorance as some of those who refuse vaccinations. I am proclaiming here that there are valid reasons to refuse to vaccinate your children, even though in my case I have (mostly) vaccinated my children against most common childhood illnesses. My rationale is that both I and my children are in contact with enough people that the probability at the moment of contracting these diseases if they weren't vaccinated is higher and the potential for their deaths, in my view and estimation, than if they weren't vaccinated. I don't claim to have 100% knowledge on this topic and I certainly don't think it is my job to make that sort of calculation for somebody else in regards to their own children. I certainly don't think it is the role of the government to force at gunpoint the vaccinations of children.
Me thinks you missed a comment in there. Yes, there can be reasons, but most people couldn't possibly know them. Herd immunity is the result of a cooperative effort where everyone takes some small risk for a very large group gain. Each person that doesn't get a vaccine increases the risk to everyone else. They are essentially saying, "I will avoid 10 units of risk in return for a thousand other people receiving an extra 1 unit of risk."
There are certainly legitimate reasons not to get a vaccine (my wife and mother in law share a vaccine allergy, so we won't be giving it to my infant son until the formula changes). But the truth is that MOST of the time when people don't vaccinate, even if it is because the individual risk from the vaccine is greater than the risk of the disease, they are being selfish and wrong.
Thanks, that's the most insightful comment I've seen in a while and answers a lot of questions.
I've been thinking about becoming a paying customer, so I'm interested in this. Is it an issue with the number of files, the total size of all files, or the size of the largest file? And do you know what the limit is?
In my office, we're heavy users of laptops because people take them to meetings, and because people want to be able to get real work done from home, and you can only VPN in with a corporate device. We're currently looking into Citrix to let our users access whatever devices they want from home. I suspect at that point most people will switch to desktops with a few tablets floating around to access stuff in meetings. A few power users need to be able to type substantial amounts in remote locations, but I suspect those will be few and far between.
Every enterprise AP maker that I've seen supports this feature. It's essentially a tick box on the feature list, and has been for a long time.
The current highest capacity wind turbines are 7.6 MW. I haven't been able to find figures on the area proposed for the collector area of this tower, but it is possible that 30-50 simpler and proven wind turbines or 1 to 5 concentrated solar units might be able to replace this tower.
Wind turbines work in a very limited number of regions. They would almost certainly be a complete failure here.
A solar concentrator would undoubtedly be more efficient per km^2, but that isn't really the point. It's worth investing in several versions of different technologies to see how well each scales, and how well each works out in the long run. Efficient solar concentrators are far more complex and have more moving parts than this system. The both cost the same initially for about the same power, while this tower takes more land area. But if it turns out that this tower lasts for 50 years with minimal maintenance, then it would be an easy win. There are many places where having low maintenance easily trumps land usage.
There are also a number of experiments that having this type of tower around would make simple, which would be otherwise impossible. For instance, what would be the climate effect of letting massive amounts of water evaporate below and be released at 2600 feet? There are a lot of interesting things you could test. Would this tower indicate an even taller tower being practical?
So basically you want to create a Meta-Power Plant. While I don't think they need the resonance aspect to it they could certainly add turbines to the outside to capture passing winds (they're doing this on some modern towers), solar underneath (instead of having a black painted floor even), and adding in geothermal (if feasible at that site) would be icing on the cake.
Solar cell power efficiency tends to drop off at temperature increases. Of course, if you can get them for cheap enough then it probably doesn't matter. I'd guess that building to carry the extra weight and stress of external turbines would not be a cost effective move. The goal is essentially a giant chimney, so anything that changes that is going to drive up costs quite a bit.
I think you don't know what you're talking about much less being confused. Emissivity defines reflectivity, as in an objects emissivity rate is it's effective reflection rate for a particular wavelength at a particular temperature, etc. etc.
Also, the solar spectrum is not most intense at the visible part. To quote Wikipedia, who has a source.
"Sunlight at zenith provides an irradiance of just over 1 kilowatt per square meter at sea level. Of this energy, 527 watts is infrared radiation, 445 watts is visible light, and 32 watts is ultraviolet radiation.[2]"
The GP's point still stands for two very important reasons, most objects emit radiation almost exclusively in the infrared and visible light is a significant source of energy. To demonstrate the importance of this, take these two situations:
Situation 1:
You have a paint A which reflects 50% of visible and 50% of infrared light. Paint B reflects 90% of visible light, but only 40% of infrared. This is more or less the situation described by the original parent where the Krylon paint has higher infrared emissivity (lower reflectivity). From the numbers you provided, paint A would be absorbing 486 Watts (527*.50+445*.50) while paint B would be absorbing 320 Watts (527*.10+445*.60). So paint B would still absorb less energy, and it would dissipate the energy more quickly as infrared radiation, while paint B would be forced to conduct more of its energy into the underlying surface.
Situation 2:
Taken to the extreme, paint C reflects 0% of visible light and 100% of infrared light. Paint D reflects 100% of visible light and 0% of infrared. Now paint D is consuming more energy than paint C, however it is simultaneously quickly dissipating most of that energy via infrared. Paint C however will probably burst into flames if its underlying surface is unable to absorb enough of the energy quickly enough.
These are both carefully crafted situations to show specifically that higher emissivity in the infrared CAN be just fine, and it's good to know that this is often not the case. The point was to clearly show the flaw in the OP's assertion that Krylon white paint having a higher emissivity in the infrared could somehow be the only fact to prove that it would be worse for covering a house.
Furthermore, and conveniently ignored, is the fact that above a certain latitude more energy is expended heating in the winter than cooling in the summer. New York City and Chicago are above that latitude, which is around 38-42 degrees on the East Coast depending on the year's average solar irradiance but varies widely across the country (because of airflow and humidity).
http://en.wikipedia.org/wiki/Insolation
Or the fact that air conditioning was never a major concern for energy conservation, since the vast majority of energy used in buildings are to heat it, not cool it.
http://www.eia.gov/kids/energy.cfm?page=us_energy_homes-basics
In very cold climates/seasons, the roofs are typically covered with snow, which negates the benefits of light absorbing roofs. Often you'll see snow melt just where the roofs are leaking heat, which is where you would would a roof with a very low emissivity in the infrared. And at those latitudes and times of the year, the amount of solar radiation available is not going to make much impact. Besides, heating energy statistics can be very misleading. For instance, the Mall of America in Minnesota runs their cooling system all year round due to the heat produced by lighting and human bodies.
IIRC, one of the reasons that traditional clay tile roofs have been around so long, particularly in warm climates, is that there is a continuous flow of air between the tiles and the underlayment due to natural convection. The tiles may get quite hot, but the air flow keeps most of that heat from reaching the rest of the building.
This is true, but white tiles would still be far better for the environment. White tiles would reflect most of the heat/light back out into the atmosphere where a fair portion of it would end up making it back into space. Regular tiles help keep the house cool, but still heat up the surrounding air, causing a slight temperature increase for everyone. Of course, one house isn't going to make a difference, but the point was that if everyone did it, then the temperature of the entire area would drop by a few degrees.
(Note that I'm not suggesting reflecting all light for an area into space as we need that light for growing plants and such. But light that gets absorbed by roofs and streets end up being bad for everyone.)
Precisely. When I lecture, I am constantly engaging the people I'm talking to, not just checking to see if they're paying attention, but honestly asking their opinions about the problems I pose. And the problems I do pose tend to be more open-ended, with no one particular right or wrong answer. ("How would you change energy policy in America?" "Do you think recycling is a good idea?" "How do you try to convey ideas using technology?")
The Khan lectures appear to focused on quantifiable topics like mathematics where there are specific right and wrong answers. Declaring it a poor idea because it doesn't work for all types of learning is missing the point.
The students go home and watch lectures about specific math topics and answer sample questions. The teacher can see which students did well and poorly on different sample questions via charts and graphs on the website. The teacher can then assign students that did well to assist those that did poorly to better understand topics, and the teacher can provide more qualified and directed assistance where needed.
Honestly, the model seems pretty ideal for that topic. For a philosophy class, it wouldn't work nearly as well, but that's not where they're trying to use it.
I used to wonder why they never marketed it widely, but now I think I've guessed: because the MD music format was already out, they might have been afraid that allowing a direct attachment to a computer would enable people to rip their music and record copies on other discs. That's exactly the kind of thinking Sony has used when it's shot itself in the foot time and time again, the only difference being this was before everyone started making MP3s.
This. Sony screwed itself over when it got into the content production market. That division has effective killed every interesting technology they've come out with in the name of keeping their content safe. (Ironic considering that there probably isn't a single piece of content they own that can't be downloaded for free from the internet.)
Had they immediately made MD-data drives available and licensed the technology out to everyone, it would have easily become a standard. Instead the smaller capacity and more expensive Zip disks picked up popularity and then quickly faded due to poor capacity and reliability problems. MiniDiscs in the US were relegated to a niche market that they died in. The computer world would have been a very different place if Sony hadn't screwed themselves over with their own greed.
When I had to use the Notes client, it was pretty terrible, but that was back in 2003, and I don't recall the version. I've known several people in the past year that have had the client at their place of work, and it seems to be universally hated, although I don't know the versions. Even if the servers are of comparable quality, it seems that the overwhelming dislike for the client would make Lotus a thing to move away from.
If you're having virus/trojan issues, then try using an edge filter of some sort. A number of companies sell them, like the Barracuda Spam Filter. Drop whatever you get between the internet and your Exchange filter and you will likely never see a virus hit Exchange. You can get a transparent proxy product to do general web browsing. That's what I do and I haven't seen a virus issue on Exchange in many years (with thousands of users).
Have you played with SharePoint 2010? 2007 was a nightmare, but I'm curious if they've fixed any of the management issues from it.
I'm baffled by the intense dislike of the Ribbon. I expected to hate it, but very quickly found it a great thing - probably one of the nicer changes that Office has seen in a long time.
Agreed. It was a little annoying in Office 2007 because some applications used it, and other didn't. Outlook 2007 didn't use it, but it was used when creating messages, which was just ridiculously inconsistent. Now that Office 2010 uses it consistently across the board, I find it better in many ways (although worse in a few). For most simple tasks, it exposes the available options better.
In my experience, most people that use it for a month or so have no complaints.
The sacrifice of resolution isn't really that big a concern. Consumer cameras have far more resolution than they need these days, as the almighty megapixel has been used as a marketing ploy even though increasing pixel density on the CCDs has led to lower image quality overall. My 10 year old 2Mpx Canon still takes better pictures than any of my wife's last 3 compact cameras (4, 5 and 8Mpx Nikon and Canons), especially in low light. I would go so far as to say it doesn't make sense to have go beyond much more than 4Mpx with lenses the size of compact cameras, as details will be lost due to lens quality long before the pixel count causes loss of detail.
I would beg to differ. Your 2 megapixel camera may produce higher quality pictures than your wife's compacts, but that likely has nothing to do with the relative resolutions. The dot pitch on decent CCDs is relatively small, so increasing the number of mega-"pixels" from 2 to 4 is going to have a negligible impact on the amount of light gathered. At best you're going to have increased resolution and sharpness that can be further used by improved processing chips. At worst you're going to reach a point where the difference in neighboring pixels is the result of noise, but will still average out the same as a lower resolution picture.
For two cameras with CMOS sensors of identical area, the biggest difference in image quality (assuming a resolution that is 'good enough' for the application) is going to be dependent on three things. The size of the lens, the quality of the lens, and the quality of the processing chip. The difference with the size of the lens is especially important the lower the environment lighting. In high light situations the lens and processing quality become more important.
If you have a large enough CMOS sensor and lens, a higher resolution camera will absolutely stomp on a lower resolution. Of course, if you're not doing any post processing and you're just displaying it on your phone, it's not going to matter.
On their website, the sample photos from their drone are basically straight down. That would severely limit the quality of the imagery on vertical walls. I'm curious why they don't angle the camera at, say, 45*. That should allow good coverage of roofs and walls.
While Firewire was undeniably a more capable and faster standard than USB2, the real reason for the difference in speeds was the quality of the controllers that were used. Had USB controllers been as high quality as Firewire controllers, very few people would have seen a difference.
Because of the high number of controllers in use, there is a lot of motivation to design more low cost controller chips. The result is that some companies will produce a barely functional USB controller at an incredibly low price. When other companies are putting together a system of some sort, saving a few pennies by getting the cheapest controller seems to make a lot of sense in savings when you talking about millions of widgets with the controllers.
In truth, the vast majority of devices didn't need a fast USB controller from a consumer perspective. There will be little difference in the speed of your keyboard, mouse, or phone sync. The end result is that people stop making more capable/expensive controllers because no one is buying them. USB quickly lost quality due to being such a commodity.
The opposite happened with Firewire. Firewire controllers were more complex, and so were just used in devices that really required the higher speeds. These were almost exclusively higher costing luxury items, where spending a few more cents for a better quality controller made sense. While there were poor quality Firewire controllers, there were still many high quality controllers being made and used because they were useful and there was a large enough market.
I'll throw in another comment in support of pfsense. It'll install on any old PC, and with that PC it will be able to handle far more connections than you'd ever be able to throw at it, while providing QoS and per system bandwidth usage. It also supports plugins so will do all sorts of other features as add-ons (like transparent caching). I have a fancy QoS wireless router that I paid >$100, and I ended up turning off all of the features to use it as an access point behind pfsense.
You never realize it until you try, but an 8 year old PC is orders of magnitude more powerful than any consumer router. The total electrical usage for me from this is ~$30/year, which I'm okay with because of the extra ability. Eventually I'll get an Atom system and cut that in half or to a third.
Regardless of the hashing algorithm, there exists a possibility of a collision.
For any modern cryptographic hashing algorithm, the only possibility of a collision is to create one on purpose, and for modern ones there haven't been methods invented to do this. IE, it's impossible as long as they routinely update their hashing algorithm (which is easy as they can produce new hashes of the files they have, and force a minimum client version for new files. When you have as many possible combinations as there are atoms in the universe, you're more likely to win every lottery for a year than to have an accidental collision.
MD5 hasn't been secure for a few years, but it relatively ancient, being created in 1991. SHA-512 has no known vulnerabilities, and a new candidate for SHA-3 will soon be chosen. Heck, they could hedge their bets and use two different hashers to in case one is ever broken.
The only real danger is if you already knew the hash of a file, you could retrieve it. Of course, the
Yeah, really heavy wheels means you lose a lot of energy for every bump you go over, having to move all of that mass up/down.
I remember in the early 90's reading a Popular Mechanics article about a (Ford?) car being developed that would use a small electric motor at each wheel, which would allow them to precisely control the speed and power of each wheel independently. The power was provided by a regular combustion engine hooked to a generator. The motor was detached from the wheel by a single axle with a universal joint at each end, allowing for a full range of motion for the wheel without the weight of the motor interfering. It looked like the energy losses would have been relatively low, so I was excited to see where it went. Of course, there was zero news about any sort of hybrid system for a decade (Ford was even longer) and none of them have anything like that design, so there were probably fundamental issues with it. I'm not really sure what they would be.
There are a lot of things that sound like great ideas, but have serious issues with implementing that you would never think of until you try.
Why bother with transmissions, crankshafts, axels, and so on? Just extra weight to haul around. Hubless eletric motors on all wheels.
The added weight makes them horribly inefficient for anything except very smooth streets. Super heavy wheels tend to be a bad thing. This concept has worked well for some things, such as city buses where the city has well paved streets.
Smaller engines like that can be ideal for running in series (either electrically or mechanically). If you have a battery pack and a few engines (they say the engines are light), then you would be able to keep one engine on for cruising, and power up other engines if you need to charge the batteries or pull a boat up hill.
Sometimes I'm a bit biased towards OSS stuff, samba in particular. For me, it's a 5 minute operation to get samba up and running, joined to an AD domain and get shares going.
I'm something of an idealist, and I really hope for the OSS versions of software in the long run. That said, even if you can get Samba to work, don't do it. Once you leave the company, what assurances do you have that anyone will have a clue what to do when something breaks?
I work at a company that had large parts of its infrastructure custom built to solve the companies unique issues, by a bunch of really brilliant people; really brilliant people who are no longer there. We are now slowly working to replace all of those pieces with well understood industry standard software packages that will be easy to upgrade or replace in the future. They may not be the perfect fit, but who cares. Over time the needs of the business change, and that perfect fit becomes a terrible fit, while the decent fit stays decent (or has a well understood migration path). And it's a lot easier to find an admin to take it over.