Not for the light-hearted, a thorough review in Reviews of Modern Physics (subscription required, if you cannot access the article, drop me an email at karvind@NOSPAM.gmail.com)
I just did quick search on slashdot and found following stories. Impressive to see so many efforts going on to restore human vision. And little more info on Retinitis Pigmentosa
Sorry folks, I forgot to put the source. I was editing and adding something and it got misplaced along with some other information. No intention of taking the credit or passing that text as my own. Multispectral solutions has a well written FAQ and needs no rewording. Thanks for pointing it out.:)
The term "ultra wideband" is a relatively new term to describe a technology which had been known since the early 1960's as "carrier-free", "baseband" or "impulse" technology. The basic concept is to develop, transmit and receive an extremely short duration burst of radio frequency (RF) energy - typically a few tens of picoseconds (trillionths of a second) to a few nanoseconds (billionths of a second) in duration. These bursts represent from one to only a few cycles of an RF carrier wave. The resultant waveforms are extremely broadband, so much so that it is often difficult to determine an actual RF center frequency - thus, the term "carrier-free". Early methods of signal generation utilized "baseband" (i.e., non-RF), fast rise-time pulse excitation of a wideband microwave antenna to generate and radiate the antenna's effective "impulse" response. (More precisely, it is the antenna's "step" response that is actually produced.) More modern UWB systems, such as those developed by MSSI, no longer utilize direct impulse excitation of an antenna because of the inability of such an approach to adequately control emission bandwidths and apparent center frequencies.
What are the advantages of UWB technology?
Since UWB waveforms are of such short time duration, they have some rather unique properties. In communications, for example, UWB pulses can be used to provide extremely high data rate performance in multi-user network applications. For radar applications, these same pulses can provide very fine range resolution and precision distance and/or positioning measurement capabilities. In fact, multifunction architectures encompassing communications, radar and positioning applications have been developed.
These short duration waveforms are relatively immune to multipath cancellation effects as observed in mobile and in-building environments. Multipath cancellation occurs when a strong reflected wave - e.g., off of a wall, ceiling, vehicle, building, etc. - arrives partially or totally out of phase with the direct path signal, causing a reduced amplitude response in the receiver. With very short pulses, the direct path has come and gone before the reflected path arrives and no cancellation occurs. As a consequence, UWB systems are particularly well suited for high-speed, mobile wireless applications. In addition, because of the extremely short duration waveforms, packet burst and time division multiple access (TDMA) protocols for multi-user communications are readily implemented.
As bandwidth is inversely related to pulse duration, the spectral extent of these waveforms can be made quite large. With proper engineering design, the resultant energy densities (i.e., transmitted Watts of power per unit Hertz of bandwidth) can be quite low. This low energy density translates into a low probability of detection (LPD) RF signature. An LPD signature is of particular interest for military applications (e.g., for covert communications and radar); however, an LPD signature also produces minimal interference to proximity systems and minimal RF health hazards, significant for both military and commercial applications.
Among the most important advantages of UWB technology, however, are those of low system complexity and low cost. UWB systems can be made nearly "all-digital", with minimal RF or microwave electronics. Because of the inherent RF simplicity of UWB designs, these systems are highly frequency adaptive, enabling them to be positioned anywhere within the RF spectrum. This feature avoids interference to existing services, while fully utilizing the available spectrum.
But are the digits truely random ? In 1996, NERSC Chief Technologist David H. Bailey, together with Canadian mathematicians Peter Borwein and Simon Plouffe, found a new formula for pi. This formula permits one to calculate the n-th binary or hexadecimal digits of pi, without having to calculate any of the preceding n-1 digits. This formula was discovered by a computer, using Bailey's implementation of Ferguson's PSLQ algorithm
CeBIT 2005 had demonstration of flash only hard drives. Since flash memory is considerably more expensive than magnetic mass storage - a hybrid approach is a better compromise.
Also from WinHEC, samsung is not the only player. The disk will be manufactured initially by Samsung, Hitachi and Seagate, and other manufacturers will be announced later.
More details on Samsung's OneNAND hybrid technology:
OneNAND Flash memory has been incorporated into the design of Microsoft Corp.'s prototype Hybrid Hard Drive (HHD), the first fully functional disk drive to combine NAND-based Flash with rotating storage media.
The hybrid hard drive prototype uses 1 Gigabit OneNAND(TM) Flash as both the write buffer and boot buffer. In the hybrid write mode, the mechanical drive is spun down for the majority of the time, while data is written to the Flash write buffer. When the write buffer is filled, the rotating drive spins and the data from the write buffer is written to the hard drive.
The hybrid drive saves power by keeping the spindle motor in idle mode almost all the time, while the operating system writes to the OneNAND write buffer. Moreover, by using OneNAND Flash with hard disk drive technology, disk drive performance is not compromised relative to conventional disk drives. This is due, in large part, to OneNAND's ultra-fast read speeds, which can be fully leveraged during the flushing of the contents of OneNAND's write buffer to the rotating drive. In addition, since the Samsung hybrid disk drive operates at a lower temperature than traditional rotating media, it greatly reduces the possibility of shock and impact damage, improving the overall reliability of the disk subsystem.
While the cost of hybrid disk drives may slightly increase with the addition of OneNAND, any increase will be mitigated by several factors, including lower maintenance costs, 95 percent power savings when the disk is not spinning, faster boot time and substantially increased reliability. All of these changes are crucial to the ever increasing needs of today's mobile customer, making it likely that hybrid hard drive technology will enjoy rapid market adoption.
Mars Rover Opportunity has wheel trouble already earlier in april. It lost the ability to steer one of its wheels. They said: While the vehicle can still move, the failure may make it harder to study rocks up close. The rover has six wheels aligned in two rows and each of the four corner wheels has its own steering mechanism. The problem is with the front right wheel, which can still roll but is now stuck at a 7 inward angle.
Also Opportunity and Spirit were given a further 18-month mission extension on 5 April 2005.
Nevertheless it is a good concept with lot of benefits (as well as drawbacks)
Cost savings. PoE significantly reduces the need for electricians to install conduit, electrical wiring, and outlets throughout the facility. In larger installations, these items can be relatively expensive. Consider an installation of 50 or more access points. This requires lots of conduits, outlet boxes, electrical wiring and the time of a qualified electrician. The low costs of deploying PoE compared to traditional electrical circuits leads to worthwhile returns on investment.
Flexible access point locations. With PoE, a wireless LAN designer has greater freedom to locate access points. You don't need to depend on only locations within short distances from AC outlets. The independence from AC outlets also makes it easier to relocate access points in the future if needed to fine-tune RF coverage or increase capacity. Thus, PoE enables companies to more easily maximize the performance of a wireless LAN.
Higher reliability. Systems with fewer wires tend to be more reliable. With WLANs not using PoE, cleaning people may unplug an access point to use its AC outlet to power vacuum and buffing equipment. Electricians rewiring electrical circuits could inadvertently cut power to an access point. PoE eliminates the possibility of situations that disrupt the operation of the network.
Enhanced operational support. Many PoE devices implement SNMP (simple network management protocol), which enables support staff to remotely manage the electrical power supplied to the access points. For example, support staff can disable a PoE-enabled access point by shutting off its power after detecting a breach of security. The temporary disabling of the access point can protect against an intruder from continuing unauthorized access to corporate systems. Other SNMP-based features enable the monitoring of the condition and consumption of power, which enhances the ability to ensure smooth and efficient network operations.
Simpler international development. For manufacturers, PoE offers the benefit of the vendor not needing to provide different power cords for various countries. This not only helps keep the cost of access points done -- it's one less piece of equipment that installers need to worry about
Interestingly in U.S., there are serious legal restrictions on the use of wiretaps by police agencies. The Supreme Court has consistently held that wiretaps qualify as searches under the Fourth Amendment.
IETF (Internet Engineering Task Force) policy on wiretapping which says: The IETF restates its strongly held belief, stated at greater
length in [RFC 1984], that both commercial development of the
Internet and adequate privacy for its users against illegal
intrusion requires the wide availability of strong cryptographic
technology.
The site has more details and has a list of additional features that are tested
Transparent PNGs -- The eyes are encoded as transparent PNGs.
The object element -- The eyes of the face are attached to an object element. Being able to use object (which can have alternative content) is one of the oldest requests from web designers.
Absolute, relative and fixed positioning -- Being able to position elements accurately is important for advanced page layouts.
Box model -- The original Acid test focused on the CSS box model. Acid2 continues in this fine tradition by testing 'height', 'width', 'max-width', 'min-width', 'max-height' and 'min-height'.
CSS tables -- There is nothing wrong with table layouts. It is a powerful layout model which makes sense on bigger screens. However, the table markup is troublesome as it ties the content to these screens. Therefore, being able to specify table layouts in CSS is important.
Margins -- CSS defines accurate algorithms for how margins around elements should be calculated.
Generated content -- The ability to add decorations and annotations to Web pages without modifying the markup has long been requested by authors.
CSS parsing -- Acid2 includes a number of illegal CSS statements that should be ignored by a compliant browser.
Paint order -- We test that overlapping content is painted in the right order. This is not a feature in itself, but a requirement for other features to work correctly.
Line heights -- The Acid2 test checks a few key parts of the CSS inline box model, upon which any standards-compliant Web page depends.
Hovering effects -- One of the elements in the face changes color when you hover over it. Which one?
Answer to this
question may differ from programmer to programmer. But I strongly feel,
it helps in Debugging, Reverse Engineering, Re-engineering, Testing and
giving the code a neat look. Moreover, it's a step towards
standardization of coding methodology.
Does anybody really know exactly how atoms and sub-atomic particles are going to behave in less-than perfect environments? What about gamma-ray bursts from stars and nuclear emissions from our Sun? Will these possibly have an adverse effect on a chip that is running on the atomic level?
One of the key to making things at nanoscale is to have fault and defect tolerance. With billions of elements in the system, you are bound to get manufacturing defects as well as many run-time defects. Even in modern DRAMs they have redundant columns of memory cells to improve the yield by swapping the defective ones with spare ones. FPGA(Field Programmable Gate Arrays) offer in-circuit reconfigurability. HP showed Teremac few years ago which had millions of defects yet it worked just "fine" by detecting the defects and reconfiguring around it.
In short there will be sources of errors and faults in these systems, but there are various ways to get around it. Also in quantum computing, you can encode your data in such a way that it is immune to noise (atleast to certain extent) and is called Quantum error correction.
But also remember that science is not just about destination but also the journey. Even if practical quantum computers are never built, we are likely to learn many interesting aspects which may be used elsewhere.
From the article: "We're pretty sure we can trap atoms -- the first step towards making a quantum memory chip," Lafyatis said. A working computer based on the design is many years away, though, he cautioned. In fact, Christandl suspects that they are at least two years away from being able to isolate one atom per trap -- the physical arrangement required for a true quantum memory device.
1. What is the working principle behind this (mechanism of trapping) ?
2. Are these experiments performed at room temperature ?
3. How do they ensure they have trapped one "desired" atom and not more atoms and not some other impurity?
4. How is the laser prevented from interfering with lattice (non-desirable interactions) ?
5. What is the decoherence time which governs if you can really do any computation before the result is lost ?
This is indeed an important step forward. But alas the student is graduating in august and I hope there is someone to followup on this work:
Theoretically, if they release the atoms above the chip in just the right way, the atoms will fall into the traps. They hope to be able to perform that final test before Christandl graduates in August.
Here is a little older article from Terri Kershner of Haverstick Consulting on LvsW. Gist: In today's rapidly changing IT environment, the tortoise can still win if the hare's only path is blocked.
Joe Zwers wrote a good article about Truth in benchmarking and how some companies blantantly manipulate data to reach marketing goals.
Slashdot coverage on earlier Linux vs Windows studies: here, here, here, here and here.
Yep, yep, probably, and maybe. These are the environmental orthodoxies I've always felt most uncomfortable with, and Brand has captured why with concise, forceful arguments.
On population, he points out that global population is close to leveling off and is declining precipitously in many countries. Why? Mostly it is the unprecedented worldwide migration from rural villages to cities, where having lots of children is less of an advantage. If those concerned with sustainability get out ahead of this trend and help guide it, it could be an environmental blessing. Cities put people close together, reducing their collective energy use. They free up rural areas for wildlife and wilderness (if protections are put in place).
Regarding biotech: There's truth to this, though it's slightly facile. It does, after all, matter that GM has been developed by giant corporations and has been used primarily for their benefit. But the idea that the technology itself is intrinsically bad... that doesn't make much sense to me. As Brand says, the proper reaction for greens ought to be to appropriate the technology and use it for their ends, particularly since, embrace or no embrace, it's gonna spread. Open-source biotech seems like a promising way for GM to do some environmental good. Brand offers some scenarios.
Ultimately, I suspect that urbanization, GM crops, and nuclear power are inevitable. If all we do is stand on the sidelines shouting "no, no, no!" the process will proceed without us, guided by the worst actors. The smartest thing that those of us concerned about the health of humanity and the planet can do is get involved and try to steer toward an outcome that is equitable and sustainable.
However, giving the bacteria a small assist with a tiny amount of electricity -- about 0.25 volts or a small fraction of the voltage needed to run a typical 6 volt cell phone -- they can leap over the fermentation barrier and convert a "dead end" fermentation product, acetic acid, into carbon dioxide and hydrogen.
The gcc tar ball has a README.SCO file (reproduced below)
The GCC team has been urged to drop support for SCO Unix from GCC, as a protest against SCO's irresponsible aggression against free software and GNU/Linux. We have decided to take no action at this time, as we no longer believe that SCO is a serious threat.
For more on the FSF's position regarding SCO's attacks on free software, please read:
http://www.gnu.org/philosophy/sco/sco.html
Superconductivity in nanotubes
on
Quantum Wires
·
· Score: 3, Informative
Article on Physics Web (1999) which explains why carbon nanotubes can be superconducting where as most of the other molecules aren't.
Two years later Sheng et al demonstrated superconductivity in carbon nanotubes. The experiment was conducted below 20K and the data collected was consistent with the Bardeen-Cooper-Schreiffer (BCS) theory of superconductivity.
For practical applications one wants the superconducting phenomenon to occur at much higher temperature.
A material becomes superconducting when its electrons pair up. Normally such negatively charged particles would repel each other, but in a positively charged crystal structure, vibrations called phonons help them get together. In carbon nanotubes, the frequency of these vibrations is very high, which, in theory at least, means superconductivity at higher temperatures.
Another field where MIT work can be useful is space antennae. Here an optical signal would initiate a sequence of changes in the shape, causing the antenna to refocus on a different point in space.
OSU had developed light-tunable plastic magnets. Here the plastic material becomes 1.5 times more magnetic when blue light shines on it. Green light partially reverses that effect.
Another interesting work is from PSU on PLZT, this new material shows a large piezoelectric effect in response to near-ultraviolet light. Piezoelectric materials convert electricity into mechanical energy -- movement. When an electric current is run through piezoelectric ceramic, the ceramic changes size -- it shrinks or expands. Certain ferroelectric materials exhibit stronger photovoltaic (light into electricity) effects. Combining these ferroelectrics with piezoelectrics (electricity into motion), researchers created a single material that would convert light directly into motion.
Wavelengths are too big: 1 micron is now a large number, and optics doesn't work much smaller than this
I am not sure what you meant by this. Modern photolithography (used in production) has optics which works well at the 193nm wavelength. EUV which is lot more complicated has optics which works all the way to 13nm wavelength.
The speeds here are limited by the gate speeds of the electronics, just like normal computers.
I think you meant interconnect delay and not switching speed of a transistor. State of the art and next generation transistors can switch in a fraction of a picosecond. On the other hand interconnects don't scale well and are the bottleneck.
Optical interconnects can break even for clock distribution were skew & crosstalk are important and the network has lot of capacitive load. That, in my opinion, will be the first place where optics will enter into microprocessors.
At Cornell we already made the Nanoguitar and Nano saxophone. Yes we were working on the nanodrums these days. No applications for auditions, we use very fast pulse lasers only:)
The peak pulsed power is 20 microwatts. Considering that the device is less than 200 nm on a side, the power density works out to about 100 million times that of the 225 hp V6 engine in a Toyota Camry.
I am not sure if I understand the power density claims. Here is a simple calculation. 20 microwatts in cube of 200nm x 200nm x 200nm will be 20 microwatts in 8 x 10^(-15) cm^3 volume. That will be a power density of 2.5 x 10^9 Watts/cm^3.
Sun's fusion power density is only ~ 2.5x10^(-4) Watts/cm^3 with core temperature around 15.7 x 10^6 K. I can understand that we wouldn't be generating the heat at peak density, but if we generate that high power desnity in nanomechanical system for even any reasonable time - wouldn't it just evaporate unless we find a very fast way of removing the power efficiently ?
I am not sure if I understand this completely (I read the Press Release).Blue gene does protein folding computations which requires hours of CPU time. How can you understand these molecular interactions in real-time ? Article doesn't give detail about how they implemented the time-consuming computation.
Slashdot Mirror
On similar theme, current issue of IEEE Spectrum has article on How to Hook Worms
Scientific American (warning: loaded with ads etc)
Not for the light-hearted, a thorough review in Reviews of Modern Physics (subscription required, if you cannot access the article, drop me an email at karvind@NOSPAM.gmail.com)
On Ferroelectric spintronics from Colossal Storage.
Spintronics and Quantum Dots. Discussion about one possible implementation.
Another good introduction.
Hope it helps.
Silicon Retinal Impants
Optobionics: surgically implanted an artificial retina into three patients who are blind from retinitis pigmentosa.
Boston Retinal Implant Project
silicon-based bionic retinas and bionic eyes (Australia)
4mm microchip is attached to a type of silicone called polydimethylsiloxane (PDMS)
Solar implants: a 2mm chip that contains about 5,000 microscopic solar cells that convert light into electrical impulses.
Sorry folks, I forgot to put the source. I was editing and adding something and it got misplaced along with some other information. No intention of taking the credit or passing that text as my own. Multispectral solutions has a well written FAQ and needs no rewording. Thanks for pointing it out. :)
The term "ultra wideband" is a relatively new term to describe a technology which had been known since the early 1960's as "carrier-free", "baseband" or "impulse" technology. The basic concept is to develop, transmit and receive an extremely short duration burst of radio frequency (RF) energy - typically a few tens of picoseconds (trillionths of a second) to a few nanoseconds (billionths of a second) in duration. These bursts represent from one to only a few cycles of an RF carrier wave. The resultant waveforms are extremely broadband, so much so that it is often difficult to determine an actual RF center frequency - thus, the term "carrier-free". Early methods of signal generation utilized "baseband" (i.e., non-RF), fast rise-time pulse excitation of a wideband microwave antenna to generate and radiate the antenna's effective "impulse" response. (More precisely, it is the antenna's "step" response that is actually produced.) More modern UWB systems, such as those developed by MSSI, no longer utilize direct impulse excitation of an antenna because of the inability of such an approach to adequately control emission bandwidths and apparent center frequencies.
What are the advantages of UWB technology?
Since UWB waveforms are of such short time duration, they have some rather unique properties. In communications, for example, UWB pulses can be used to provide extremely high data rate performance in multi-user network applications. For radar applications, these same pulses can provide very fine range resolution and precision distance and/or positioning measurement capabilities. In fact, multifunction architectures encompassing communications, radar and positioning applications have been developed. These short duration waveforms are relatively immune to multipath cancellation effects as observed in mobile and in-building environments. Multipath cancellation occurs when a strong reflected wave - e.g., off of a wall, ceiling, vehicle, building, etc. - arrives partially or totally out of phase with the direct path signal, causing a reduced amplitude response in the receiver. With very short pulses, the direct path has come and gone before the reflected path arrives and no cancellation occurs. As a consequence, UWB systems are particularly well suited for high-speed, mobile wireless applications. In addition, because of the extremely short duration waveforms, packet burst and time division multiple access (TDMA) protocols for multi-user communications are readily implemented. As bandwidth is inversely related to pulse duration, the spectral extent of these waveforms can be made quite large. With proper engineering design, the resultant energy densities (i.e., transmitted Watts of power per unit Hertz of bandwidth) can be quite low. This low energy density translates into a low probability of detection (LPD) RF signature. An LPD signature is of particular interest for military applications (e.g., for covert communications and radar); however, an LPD signature also produces minimal interference to proximity systems and minimal RF health hazards, significant for both military and commercial applications. Among the most important advantages of UWB technology, however, are those of low system complexity and low cost. UWB systems can be made nearly "all-digital", with minimal RF or microwave electronics. Because of the inherent RF simplicity of UWB designs, these systems are highly frequency adaptive, enabling them to be positioned anywhere within the RF spectrum. This feature avoids interference to existing services, while fully utilizing the available spectrum.
ScienceNews article (2001) on Randomness of Pi's digits
Interesting work from Johan on Testing the a-periodic randomness of and comparing it with a Quantum Mechanical source.
But are the digits truely random ? In 1996, NERSC Chief Technologist David H. Bailey, together with Canadian mathematicians Peter Borwein and Simon Plouffe, found a new formula for pi. This formula permits one to calculate the n-th binary or hexadecimal digits of pi, without having to calculate any of the preceding n-1 digits. This formula was discovered by a computer, using Bailey's implementation of Ferguson's PSLQ algorithm
Also from WinHEC, samsung is not the only player. The disk will be manufactured initially by Samsung, Hitachi and Seagate, and other manufacturers will be announced later.
More details on Samsung's OneNAND hybrid technology:
OneNAND Flash memory has been incorporated into the design of Microsoft Corp.'s prototype Hybrid Hard Drive (HHD), the first fully functional disk drive to combine NAND-based Flash with rotating storage media.
The hybrid hard drive prototype uses 1 Gigabit OneNAND(TM) Flash as both the write buffer and boot buffer. In the hybrid write mode, the mechanical drive is spun down for the majority of the time, while data is written to the Flash write buffer. When the write buffer is filled, the rotating drive spins and the data from the write buffer is written to the hard drive.
The hybrid drive saves power by keeping the spindle motor in idle mode almost all the time, while the operating system writes to the OneNAND write buffer. Moreover, by using OneNAND Flash with hard disk drive technology, disk drive performance is not compromised relative to conventional disk drives. This is due, in large part, to OneNAND's ultra-fast read speeds, which can be fully leveraged during the flushing of the contents of OneNAND's write buffer to the rotating drive. In addition, since the Samsung hybrid disk drive operates at a lower temperature than traditional rotating media, it greatly reduces the possibility of shock and impact damage, improving the overall reliability of the disk subsystem.
While the cost of hybrid disk drives may slightly increase with the addition of OneNAND, any increase will be mitigated by several factors, including lower maintenance costs, 95 percent power savings when the disk is not spinning, faster boot time and substantially increased reliability. All of these changes are crucial to the ever increasing needs of today's mobile customer, making it likely that hybrid hard drive technology will enjoy rapid market adoption.
Also Opportunity and Spirit were given a further 18-month mission extension on 5 April 2005.
The Power over ethernet website which has links to articles and products (check the dates on some of the articles).
A good article about ins and outs of PoE
Don't confuse PoE with Perl Object Environment or Poe Puzzle
Nevertheless it is a good concept with lot of benefits (as well as drawbacks)
Cost savings. PoE significantly reduces the need for electricians to install conduit, electrical wiring, and outlets throughout the facility. In larger installations, these items can be relatively expensive. Consider an installation of 50 or more access points. This requires lots of conduits, outlet boxes, electrical wiring and the time of a qualified electrician. The low costs of deploying PoE compared to traditional electrical circuits leads to worthwhile returns on investment.
Flexible access point locations. With PoE, a wireless LAN designer has greater freedom to locate access points. You don't need to depend on only locations within short distances from AC outlets. The independence from AC outlets also makes it easier to relocate access points in the future if needed to fine-tune RF coverage or increase capacity. Thus, PoE enables companies to more easily maximize the performance of a wireless LAN.
Higher reliability. Systems with fewer wires tend to be more reliable. With WLANs not using PoE, cleaning people may unplug an access point to use its AC outlet to power vacuum and buffing equipment. Electricians rewiring electrical circuits could inadvertently cut power to an access point. PoE eliminates the possibility of situations that disrupt the operation of the network.
Enhanced operational support. Many PoE devices implement SNMP (simple network management protocol), which enables support staff to remotely manage the electrical power supplied to the access points. For example, support staff can disable a PoE-enabled access point by shutting off its power after detecting a breach of security. The temporary disabling of the access point can protect against an intruder from continuing unauthorized access to corporate systems. Other SNMP-based features enable the monitoring of the condition and consumption of power, which enhances the ability to ensure smooth and efficient network operations.
Simpler international development. For manufacturers, PoE offers the benefit of the vendor not needing to provide different power cords for various countries. This not only helps keep the cost of access points done -- it's one less piece of equipment that installers need to worry about
Our old story on VoIP Wiretapping
Interestingly in U.S., there are serious legal restrictions on the use of wiretaps by police agencies. The Supreme Court has consistently held that wiretaps qualify as searches under the Fourth Amendment.
Article on related topic of Open Internet Wiretapping: Carnivore
IETF (Internet Engineering Task Force) policy on wiretapping which says: The IETF restates its strongly held belief, stated at greater length in [RFC 1984], that both commercial development of the Internet and adequate privacy for its users against illegal intrusion requires the wide availability of strong cryptographic technology.
Another issue: Is Dialing Into a Conference Call an Interception?
I discovered it yesterday
Transparent PNGs -- The eyes are encoded as transparent PNGs.
The object element -- The eyes of the face are attached to an object element. Being able to use object (which can have alternative content) is one of the oldest requests from web designers.
Absolute, relative and fixed positioning -- Being able to position elements accurately is important for advanced page layouts.
Box model -- The original Acid test focused on the CSS box model. Acid2 continues in this fine tradition by testing 'height', 'width', 'max-width', 'min-width', 'max-height' and 'min-height'.
CSS tables -- There is nothing wrong with table layouts. It is a powerful layout model which makes sense on bigger screens. However, the table markup is troublesome as it ties the content to these screens. Therefore, being able to specify table layouts in CSS is important.
Margins -- CSS defines accurate algorithms for how margins around elements should be calculated.
Generated content -- The ability to add decorations and annotations to Web pages without modifying the markup has long been requested by authors.
CSS parsing -- Acid2 includes a number of illegal CSS statements that should be ignored by a compliant browser.
Paint order -- We test that overlapping content is painted in the right order. This is not a feature in itself, but a requirement for other features to work correctly.
Line heights -- The Acid2 test checks a few key parts of the CSS inline box model, upon which any standards-compliant Web page depends.
Hovering effects -- One of the elements in the face changes color when you hover over it. Which one?
An interesting article on ZDNet on Documentation is good, but source code is better
Good documentation practice from Linux.com.
One of the key to making things at nanoscale is to have fault and defect tolerance. With billions of elements in the system, you are bound to get manufacturing defects as well as many run-time defects. Even in modern DRAMs they have redundant columns of memory cells to improve the yield by swapping the defective ones with spare ones. FPGA(Field Programmable Gate Arrays) offer in-circuit reconfigurability. HP showed Teremac few years ago which had millions of defects yet it worked just "fine" by detecting the defects and reconfiguring around it.
In short there will be sources of errors and faults in these systems, but there are various ways to get around it. Also in quantum computing, you can encode your data in such a way that it is immune to noise (atleast to certain extent) and is called Quantum error correction.
But also remember that science is not just about destination but also the journey. Even if practical quantum computers are never built, we are likely to learn many interesting aspects which may be used elsewhere.
1. What is the working principle behind this (mechanism of trapping) ?
2. Are these experiments performed at room temperature ?
3. How do they ensure they have trapped one "desired" atom and not more atoms and not some other impurity?
4. How is the laser prevented from interfering with lattice (non-desirable interactions) ?
5. What is the decoherence time which governs if you can really do any computation before the result is lost ?
This is indeed an important step forward. But alas the student is graduating in august and I hope there is someone to followup on this work:
Theoretically, if they release the atoms above the chip in just the right way, the atoms will fall into the traps. They hope to be able to perform that final test before Christandl graduates in August.
Joe Zwers wrote a good article about Truth in benchmarking and how some companies blantantly manipulate data to reach marketing goals.
Slashdot coverage on earlier Linux vs Windows studies: here, here, here, here and here.
We also coverd a Microsoft study on W vs L
On population, he points out that global population is close to leveling off and is declining precipitously in many countries. Why? Mostly it is the unprecedented worldwide migration from rural villages to cities, where having lots of children is less of an advantage. If those concerned with sustainability get out ahead of this trend and help guide it, it could be an environmental blessing. Cities put people close together, reducing their collective energy use. They free up rural areas for wildlife and wilderness (if protections are put in place).
Regarding biotech: There's truth to this, though it's slightly facile. It does, after all, matter that GM has been developed by giant corporations and has been used primarily for their benefit. But the idea that the technology itself is intrinsically bad ... that doesn't make much sense to me. As Brand says, the proper reaction for greens ought to be to appropriate the technology and use it for their ends, particularly since, embrace or no embrace, it's gonna spread. Open-source biotech seems like a promising way for GM to do some environmental good. Brand offers some scenarios.
Ultimately, I suspect that urbanization, GM crops, and nuclear power are inevitable. If all we do is stand on the sidelines shouting "no, no, no!" the process will proceed without us, guided by the worst actors. The smartest thing that those of us concerned about the health of humanity and the planet can do is get involved and try to steer toward an outcome that is equitable and sustainable.
However, giving the bacteria a small assist with a tiny amount of electricity -- about 0.25 volts or a small fraction of the voltage needed to run a typical 6 volt cell phone -- they can leap over the fermentation barrier and convert a "dead end" fermentation product, acetic acid, into carbon dioxide and hydrogen.
I agree, it is written poorly.
The GCC team has been urged to drop support for SCO Unix from GCC, as a protest against SCO's irresponsible aggression against free software and GNU/Linux. We have decided to take no action at this time, as we no longer believe that SCO is a serious threat.
For more on the FSF's position regarding SCO's attacks on free software, please read:
http://www.gnu.org/philosophy/sco/sco.html
Two years later Sheng et al demonstrated superconductivity in carbon nanotubes. The experiment was conducted below 20K and the data collected was consistent with the Bardeen-Cooper-Schreiffer (BCS) theory of superconductivity.
For practical applications one wants the superconducting phenomenon to occur at much higher temperature. A material becomes superconducting when its electrons pair up. Normally such negatively charged particles would repel each other, but in a positively charged crystal structure, vibrations called phonons help them get together. In carbon nanotubes, the frequency of these vibrations is very high, which, in theory at least, means superconductivity at higher temperatures.
OSU had developed light-tunable plastic magnets. Here the plastic material becomes 1.5 times more magnetic when blue light shines on it. Green light partially reverses that effect.
Another interesting work is from PSU on PLZT, this new material shows a large piezoelectric effect in response to near-ultraviolet light. Piezoelectric materials convert electricity into mechanical energy -- movement. When an electric current is run through piezoelectric ceramic, the ceramic changes size -- it shrinks or expands. Certain ferroelectric materials exhibit stronger photovoltaic (light into electricity) effects. Combining these ferroelectrics with piezoelectrics (electricity into motion), researchers created a single material that would convert light directly into motion.
I am not sure what you meant by this. Modern photolithography (used in production) has optics which works well at the 193nm wavelength. EUV which is lot more complicated has optics which works all the way to 13nm wavelength.
The speeds here are limited by the gate speeds of the electronics, just like normal computers.
I think you meant interconnect delay and not switching speed of a transistor. State of the art and next generation transistors can switch in a fraction of a picosecond. On the other hand interconnects don't scale well and are the bottleneck.
Optical interconnects can break even for clock distribution were skew & crosstalk are important and the network has lot of capacitive load. That, in my opinion, will be the first place where optics will enter into microprocessors.
At Cornell we already made the Nanoguitar and Nano saxophone. Yes we were working on the nanodrums these days. No applications for auditions, we use very fast pulse lasers only :)
I am not sure if I understand the power density claims. Here is a simple calculation. 20 microwatts in cube of 200nm x 200nm x 200nm will be 20 microwatts in 8 x 10^(-15) cm^3 volume. That will be a power density of 2.5 x 10^9 Watts/cm^3.
Sun's fusion power density is only ~ 2.5x10^(-4) Watts/cm^3 with core temperature around 15.7 x 10^6 K. I can understand that we wouldn't be generating the heat at peak density, but if we generate that high power desnity in nanomechanical system for even any reasonable time - wouldn't it just evaporate unless we find a very fast way of removing the power efficiently ?
I am not sure if I understand this completely (I read the Press Release).Blue gene does protein folding computations which requires hours of CPU time. How can you understand these molecular interactions in real-time ? Article doesn't give detail about how they implemented the time-consuming computation.