Computers With 'Common Sense'

Source:

http://www.sciencedaily.com/releases/2007/10/071017174328.htm

ScienceDaily (Oct. 18, 2007) — Using a little-known Google Labs widget, computer scientists from UC San Diego and UCLA have brought common sense to an automated image labeling system. This common sense is the ability to use context to help identify objects in photographs.

For example, if a conventional automated object identifier has labeled a person, a tennis racket, a tennis court and a lemon in a photo, the new post-processing context check will re-label the lemon as a tennis ball.
“We think our paper is the first to bring external semantic context to the problem of object recognition,” said computer science professor Serge Belongie from UC San Diego.
The researchers show that the Google Labs tool called Google Sets can be used to provide external contextual information to automated object identifiers.
Google Sets generates lists of related items or objects from just a few examples. If you type in John, Paul and George, it will return the words Ringo, Beatles and John Lennon. If you type “neon” and “argon” it will give you the rest of the noble gasses.
“In some ways, Google Sets is a proxy for common sense. In our paper, we showed that you can use this common sense to provide contextual information that improves the accuracy of automated image labeling systems,” said Belongie.
The image labeling system is a three step process. First, an automated system splits the image up into different regions through the process of image segmentation. In the photo above, image segmentation separates the person, the court, the racket and the yellow sphere.
Next, an automated system provides a ranked list of probable labels for each of these image regions.
Finally, the system adds a dose of context by processing all the different possible combinations of labels within the image and maximizing the contextual agreement among the labeled objects within each picture.
It is during this step that Google Sets can be used as a source of context that helps the system turn a lemon into a tennis ball. In this case, these “semantic context constraints” helped the system disambiguate between visually similar objects.
In another example, the researchers show that an object originally labeled as a cow is (correctly) re-labeled as a boat when the other objects in the image – sky, tree, building and water – are considered during the post-processing context step. In this case, the semantic context constraints helped to correct an entirely wrong image label. The context information came from the co-occurrence of object labels in the training sets rather than from Google Sets.
The computer scientists also highlight other advances they bring to automated object identification. First, instead of doing just one image segmentation, the researchers generated a collection of image segmentations and put together a shortlist of stable image segmentations. This increases the accuracy of the segmentation process and provides an implicit shape description for each of the image regions.
Second, the researchers ran their object categorization model on each of the segmentations, rather than on individual pixels. This dramatically reduced the computational demands on the object categorization model.
In the two sets of images that the researchers tested, the categorization results improved considerably with inclusion of context. For one image dataset, the average categorization accuracy increased more than 10 percent using the semantic context provided by Google Sets. In a second dataset, the average categorization accuracy improved by about 2 percent using the semantic context provided by Google Sets. The improvements were higher when the researchers gleaned context information from data on co-occurrence of object labels in the training data set for the object identifier.
Right now, the researchers are exploring ways to extend context beyond the presence of objects in the same image. For example, they want to make explicit use of absolute and relative geometric relationships between objects in an image – such as “above” or “inside” relationships. This would mean that if a person were sitting on top of an animal, the system would consider the animal to be more likely a horse than a dog.
Reference: “Objects in Context,” by Andrew Rabinovich, Carolina Galleguillos, Eric Wiewiora and Serge Belongie from the Department of Computer Science and Engineering at the UCSD Jacobs School of Engineering. Andrea Vedaldi from the Department of Computer Science, UCLA.
The paper will be presented on Thursday 18 October 2007 at ICCV 2007 – the 11th IEEE International Conference on Computer Vision in Rio de Janeiro, Brazil.
Funders: National Science Foundation, Afred P. Sloan Research Fellowship, Air Force Office of Scientific Research, Office of Naval Research.
Adapted from materials provided by University of California - San Diego.

Fausto Intilla

www.oloscience.com

Thwarting The Growth Of Internet Black Markets

Source:

http://www.sciencedaily.com/releases/2007/10/071015102827.htm

Science Daily — Carnegie Mellon University's Adrian Perrig and Jason Franklin, working in conjunction with Vern Paxson of the International Computer Science Institute and Stefan Savage of the University of California, San Diego, have designed new computer tools to better understand and potentially thwart the growth of Internet black markets, where attackers use well-developed business practices to hawk viruses, stolen data and attack services.
"These troublesome entrepreneurs even offer tech support and free updates for their malicious creations that run the gamut from denial of service attacks designed to overwhelm Web sites and servers to data stealing Trojan viruses," said Perrig, an associate professor of electrical and computer engineering and engineering and public policy.
In order to understand the millions of lines of data derived from monitoring the underground markets for more than seven months, Carnegie Mellon researchers developed automated techniques to measure and catalogue the activities of the shadowy online crooks who profit from spewed spam, virus-laden PCs and identity theft. The researchers estimate that the total value of the illegal materials available for sale in the seven-month period could total more than $37 million.
"Our research monitoring found that more than 80,000 potential credit card numbers were available through these illicit underground web economies," said Franklin, a Ph.D. student in computer science. However, the researchers warned that because checking the validity of the card numbers was not possible without credit card company assistance, the cards seen may not have been valid when they were observed.
Whatever the purchases, a buyer will typically contact the black market vendor privately using email, or in some cases, a private instant message. Money generally changes hands through non-bank payment services such as e-gold, making the criminals difficult to track.
To stem the flow of stolen credit cards and identity data, Carnegie Mellon researchers proposed two technical approaches to reduce the number of successful market transactions, including a slander attack and another technique, which were aimed at undercutting the cyber-crooks verification or reputation system.
"Just like you need to verify that individuals are honest on E-bay, online criminals need to verify that they are dealing with 'honest' criminals," Franklin said.
In a slander attack, an attacker eliminates the verified status of a buyer or seller through false defamation. "By eliminating the verified status of the honest individuals, an attacker establishes a lemon market where buyers are unable to distinguish the quality of the goods or services," Franklin said.
The researchers also propose to undercut the burgeoning black market activity by creating a deceptive sales environment.
Perrig's team developed a technique to establish fake verified-status identities that are difficult to distinguish from other-verified status sellers making it hard for buyers to identify the honest verified-status sellers from dishonest verified-status sellers.
"So, when the unwary buyer tries to collect the goods and services promised, the seller fails to provide the goods and services. Such behavior is known as 'ripping.' And it is the goal of all black market site's verification systems to minimize such behavior," said Franklin.
There have been successful takedowns against known black market sites, such as the U.S. Secret Service-run Operation Firewall three years ago. That operation against the notorious Shadowcrew resulted in 28 arrests around the globe, Carnegie Mellon researchers reported.
"The scary thing about all this is that you do not have to be in the know to find black markets, they are easy to find, easy to join and just a mouse click away," Franklin said.
"We believe these black markets are growing, so we will have even more incidents to monitor and study in the future," Perrig said.
That growth is also reflected in the latest Computer Security Institute (CSI) Computer Crime and Security Survey that shows average cyber-losses more than doubled after a five-year decline. The 2007 CSI survey reported that U.S. companies on average lost more than $300,000 to cyber crooks compared to $168,000 last year.
Note: This story has been adapted from material provided by Carnegie Mellon University.

Fausto Intilla
www.oloscience.com

Computer Security Can Double As Help For The Blind

Source:

http://www.sciencedaily.com/releases/2007/10/071015093548.htm

Science Daily — Before you can post a comment to most blogs, you have to type in a series of distorted letters and numbers (a CAPTCHA) to prove that you are a person and not a computer attempting to add comment spam to the blog.

What if -- instead of wasting your time and energy typing something meaningless like SGO9DXG -- you could label an image or perform some other quick task that will help someone who is visually impaired do their grocery shopping?
In a position paper presented at Interactive Computer Vision (ICV) 2007 on October 15 in Rio de Janeiro, computer scientists from UC San Diego led by professor Serge Belongie outline a grid system that would allow CAPTCHAs to be used for this purpose -- and an endless number of other good causes.
"One of the application areas for my research is assistive technologyfor the blind. For example, there is an enormous amount of data that needs to be labeled for our grocery shopping aid to work. We are developing a wearable computer with a camera that can lead a visually impaired user to a desired product in a grocery store by analyzing the video stream. Our paper describes a way that people who are looking to prove that they are humans and not computers can help label still shots from video streams in real time," said Belongie.
The researchers call their system a "Soylent grid" which is a reference to the 1973 film Soylent Green (see more on this reference at the end of the article).
"The degree to which human beings could participate in the system (as remote sighted guides) ranges from none at all to virtually unlimited. If no human user is involved in the loop, only computer vision algorithms solve the identification problem. But in principle, if there were an unlimited number of humans in the loop, all the video frames could be submitted to a SOYLENT GRID, be solved immediately and sent back to the device to guide the user," the authors write in their paper.
From the front end, users who want to post a comment on a blog would be asked to perform a variety of tasks, instead of typing in a string of misshapen letters and numbers.
"You might be asked to click on the peanut butter jar or click the Cheetos bag in an image," said Belongie. "This would be one of the so called 'Where's Waldo' object detection tasks."
The task list also includes "Name that Thing" (object recognition), "Trace This" (image segmentation) and "Hot or Not" (choosing visually pleasing images).
"Our research on the personal shopper for the visually impaired -- called Grozi -- is a big motivation for this project. When we started the Grozi project, one of the students, Michele Merler -- who is now working on a Ph.D. at Columbia University -- captured 45 minutes of video footage from the campus grocery store and then endured weeks of manually intensive labor, drawing bounding boxes and identifying the 120 products we focused on. This is work the soylent grid could do," said Belongie.
From the back end, researchers and others who need images labeled would interact with clients (like a blog hosting company) that need to take advantage of the CAPTCHA and spam filtering capabilities of the grid.
"Getting this done is going to take an innovative collaboration between academia and industry. Calit2 could be uniquely instrumental in this project," said Belongie. "Right now we are working on a proposal that will outline exactly what we need -- access to X number of CAPTCHA requests in one week, for example. With this, we'll do a case study and demonstrate just how much data can be labeled with 99 percent reliability through the soylent grid. I'm hoping for people to say, 'Wow, I didn't know that kind of computation was available.'"
This work incorporates recent work from a variety of researchers, including computer scientist Luis von Ahn from Carnegie Mellon University. His reCAPTCHA project uses CAPTCHAs to digitize books.
Soylent Grid?
The researchers call their system a "Soylent grid" and titled their paper "Soylent Grid: it's Made of People! Both the grid name and paper name are references to the 1973 cult classic film Soylent Green, a dystopian science fiction film set in an overpopulated world in which the masses are reduced to eating different varieties of "soylent" -- a synthetic food that suggests both soybeans and lentils. The line from the movie that inspired the title of this paper comes is delivered when someone discovers that soylent green is actually made of cadavers from a government sponsored euthanasia program -- prompting the phrase "Soylent green, it's made of people!" The computer scientists are playing off this famous phrase with their title: "Soylent Grid: it's Made of People!" The idea being that people from all over the world need to jump through anti-spam hoops such as CAPTCHAs, and the power of these people can be harnessed through a grid structure to do some good in the world.
Article: "Soylent Grid: it's Made of People!" by Stephan Steinbach, Vincent Rabaud and Serge Belongie
Note: This story has been adapted from material provided by University of California - San Diego.

Fausto Intilla

www.oloscience.com

Quantum Computing Possibilites Enhanced With New Material

Source:

http://www.sciencedaily.com/releases/2007/10/071008103647.htm

Science Daily — Scientists at Florida State University's National High Magnetic Field Laboratory and the university's Department of Chemistry and Biochemistry have introduced a new material that could be to computers of the future what silicon is to the computers of today.

The material -- a compound made from the elements potassium, niobium and oxygen, along with chromium ions -- could provide a technological breakthrough that leads to the development of new quantum computing technologies. Quantum computers would harness the power of atoms and molecules to perform memory and processing tasks on a scale far beyond those of current computers.
"The field of quantum information technology is in its infancy, and our work is another step forward in this fascinating field," said Saritha Nellutla, a postdoctoral associate at the magnet lab and lead author of the paper published in Physical Review Letters.
Semiconductor technology is close to reaching its performance limit. Over the years, processors have shrunk to their current size, with the components of a computer chip more than 1,000 times smaller than the thickness of a human hair. At those very small scales, quantum effects -- behaviors in matter that occur at the atomic and subatomic levels -- can start playing a role. By exploiting those behaviors, scientists hope to take computing to the next level.
In current computers, the basic unit of information is the "bit," which can have a value of 0 or 1. In so-called quantum computers, which currently exist only in theory, the basic unit is the "qubit" (short for quantum bit). A qubit can have not only a value of 0 or 1, but also all kinds of combinations of 0 and 1 -- including 0 and 1 at the same time -- meaning quantum computers could perform certain kinds of calculations much more effectively than current ones.
How scientists realize the promise of the theoretical qubit is not clear. Various designs and paths have been proposed, and one very promising idea is to use tiny magnetic fields, called "spins." Spins are associated with electrons and various atomic nuclei.
Magnet lab scientists used high magnetic fields and microwave radiation to "operate" on the spins in the new material they developed to get an indication of how long the spin could be controlled. Based on their experiments, the material could enable 500 operations in 10 microseconds before losing its ability to retain information, making it a good candidate for a qubit.
Putting this spin to work would usher in a technological revolution, because the spin state of an electron, in addition to its charge, could be used to carry, manipulate and store information.
"This material is very promising," said Naresh Dalal, a professor of chemistry and biochemistry at FSU and one of the paper's authors. "But additional synthetic and magnetic characterization work is needed before it could be made suitable for use in a device."
Dalal also serves as an adviser to FSU chemistry graduate student Mekhala Pati, who created the material.
Note: This story has been adapted from material provided by Florida State University.

Fausto Intilla

www.oloscience.com

Running Shipwreck Simulations Backwards Helps Identify Dangerous Waves

Source:

http://www.sciencedaily.com/releases/2007/10/071001165915.htm

Science Daily — Big waves in fierce storms have long been the focus of ship designers in simulations testing new vessels.
But a new computer program and method of analysis by University of Michigan researchers makes it easy to see that a series of smaller waves—a situation much more likely to occur—could be just as dangerous.
"Like the Edmund Fitzgerald that sank in Michigan in 1975, many of the casualties that happen occur in circumstances that aren't completely understood, and therefore they are difficult to design for," said Armin Troesch, professor of naval architecture and marine engineering. "This analysis method and program gives ship designers a clearer picture of what they're up against."
Troesch and doctoral candidate Laura Alford will present a paper on their findings Oct. 2 at the International Symposium on Practical Design of Ships and Other Floating Structures, also known as PRADS 2007.
Today's ship design computer modeling programs are a lot like real life, in that they go from cause to effect. A scientist tells the computer what type of environmental conditions to simulate, asking, in essence, "What would waves like this do to this ship?" The computer answers with how the boat is likely to perform.
Alford and Troesch's method goes backwards, from effect to cause. To use their program, a scientist enters a particular ship response, perhaps the worst case scenario. The question this time is more like, "What are the possible wave configurations that could make this ship experience the worst case scenario?" The computer answers with a list of water conditions.
What struck the researchers when they performed their analysis was that quite often, the biggest ship response is not caused by the biggest waves. Wave height is only one contributing factor. Others are wave grouping, wave period (the amount of time between wave crests), and wave direction.
"In a lot of cases, you could have a rare response, but when we looked at just the wave heights that caused that response, we found they're not so rare," Alford said. "This is about operational conditions and what you can be safely sailing in. The safe wave height might be lower than we thought."
This new method is much faster than current simulations. Computational fluid dynamics modeling in use now works by subjecting the virtual ship to random waves. This method is extremely computationally intensive and a ship designer would have to go through months of data to pinpoint the worst case scenario.
Alford and Troesch's program and method of analysis takes about an hour. And it gives multiple possible wave configurations that could have statistically caused the end result.
There's an outcry in the shipping industry for advanced ship concepts, including designs with more than one hull, Troesch said. But because ships are so large and expensive to build, prototypes are uncommon. This new method is meant to be used in the early stages of design to rule out problematic architectures. And it is expected to help spur innovation.
A majority of international goods are still transported by ship, Troesch said.
The paper is called "A Methodology for Creating Design Ship Responses."
Note: This story has been adapted from material provided by University of Michigan.

Fausto Intilla
www.oloscience.com

Software 'Chipper' Speeds Debugging

Source:

http://www.sciencedaily.com/releases/2007/10/071002135536.htm

Science Daily — Computer scientists at UC Davis have developed a technique to speed up program debugging by automatically "chipping" the software into smaller pieces so that bugs can be isolated more easily.
Computer programs consist of thousands, tens or even hundreds of thousands of lines of code. To isolate a bug in the code, programmers often break it into smaller pieces until they can pin down the error in a smaller stretch that is easier to manage. UC Davis graduate student Chad Sterling and Ron Olsson, professor of computer science, set out to automate that process.
"It's really tedious to go through thousands of lines of code," Olsson said.
The "Chipper" tools developed by Sterling and Olsson chip off pieces of software while preserving the program structure.
"The pieces have to work after they are cut down," Olsson said. "You can't just cut in mid-sentence."
In a recent paper in the journal "Software -- Practice and Experience," Olsson and Sterling describe ChipperJ, a version developed for the Java programming language. ChipperJ was able to reduce large programs to 20 to 35 percent of their former size in under an hour.
More information about automated program chipping is available on Olsson's Web site at http://www.cs.ucdavis.edu/~olsson/
Note: This story has been adapted from material provided by University of California, Davis.

Fausto Intilla
www.oloscience.com

'Dead Time' Limits Quantum Cryptography Speeds

Source:

http://www.sciencedaily.com/releases/2007/09/070928104257.htm

Science Daily — Quantum cryptography is potentially the most secure method of sending encrypted information, but does it have a speed limit" According to a new paper* by researchers at the National Institute of Standards and Technology (NIST) and the Joint Quantum Institute** (JQI), technological and security issues will stall maximum transmission rates at levels comparable to that of a single broadband connection, such as a cable modem, unless researchers reduce "dead times" in the detectors that receive quantum-encrypted messages.
In quantum cryptography, a sender, usually designated Alice, transmits single photons, or particles of light, encoding 0s and 1s to a recipient, "Bob." The photons Bob receives and correctly measures make up the secret "key" that is used to decode a subsequent message. Because of the quantum rules, an eavesdropper, "Eve," cannot listen in on the key transmission without being detected, but she could monitor a more traditional communication (such as a phone call) that must take place between Alice and Bob to complete their communication.
Modern telecommunications hardware easily allows Alice to transmit photons at rates much faster than any Internet connection. But at least 90 percent (and more commonly 99.9 percent) of the photons do not make it to Bob's detectors, so that he receives only a small fraction of the photons sent by Alice. Alice can send more photons to Bob by cranking up the speed of her transmitter, but then, they'll run into problems with the detector's "dead time," the period during which the detector needs to recover after it detects a photon. Commercially available single-photon detectors need about 50-100 nanoseconds to recover before they can detect another photon, much slower than the 1 nanosecond between photons in a 1-Ghz transmission.
Not only does dead time limit the transmission rate of a message, but it also raises security issues for systems that use different detectors for 0s and 1s. In that important "phone call," Bob must report the time of each detection event. If he reports two detections occurring within the dead time of his detectors, then Eve can deduce that they could not have come from the same detector and correspond to opposite bit values.
Sure, Bob can choose not to report the second, closely spaced photon, but this further decreases the key production rate. And for the most secure type of encryption, known as a one-time pad, the key has to have as many bits of information as the message itself.
The speed limit would go up, says NIST physicist Joshua Bienfang, if researchers reduce the dead time in single-photon detectors, something that several groups are trying to do. According to Bienfang, higher speeds also would be useful for wireless cryptography between a ground station and a satellite in low-Earth orbit. Since the two only would be close enough to communicate for a small part of the day, it would be beneficial to send as much information as possible during a short time window.
* D.J. Rogers, J.C. Bienfang, A. Nakassis, H. Xu and C.W. Clark, Detector dead-time effects and paralyzability in high-speed quantum key distribution, New Journal of Physics (September 2007);EJ/abstract/-kwd=nj-2f2/1367-2630/9/9/319.
**The JQI is a research partnership that includes NIST and the University of Maryland.
Note: This story has been adapted from material provided by National Institute of Standards and Technology.

Fausto Intilla
www.oloscience.com

Superconducting Quantum Computing Cable Created

Source:

http://www.sciencedaily.com/releases/2007/09/070926172232.htm

Science Daily — Physicists at the National Institute of Standards and Technology (NIST) have transferred information between two "artificial atoms" by way of electronic vibrations on a microfabricated aluminum cable, demonstrating a new component for potential ultra-powerful quantum computers of the future.

The setup resembles a miniature version of a cable-television transmission line, but with some powerful added features, including superconducting circuits with zero electrical resistance, and multi-tasking data bits that obey the unusual rules of quantum physics.
The resonant cable might someday be used in quantum computers, which would rely on quantum behavior to carry out certain functions, such as code-breaking and database searches, exponentially faster than today's most powerful computers.
Moreover, the superconducting components in the NIST demonstration offer the possibility of being easier to manufacture and scale up to a practical size than many competing candidates, such as individual atoms, for storing and transporting data in quantum computers.
Unlike traditional electronic devices, which store information in the form of digital bits that each possess a value of either 0 or 1, each superconducting circuit acts as a quantum bit, or qubit, which can hold values of 0 and 1 at the same time. Qubits in this "superposition" of both values may allow many more calculations to be performed simultaneously than is possible with traditional digital bits, offering the possibility of faster and more powerful computing devices. The resonant section of cable shuttling the information between the two superconducting circuits is known to engineers as a "quantum bus," and it could transport data between two or more qubits.
The NIST work is featured on the cover of the Sept. 27 issue of Nature. The scientists encoded information in one qubit, transferred this information as microwave energy to the resonant section of cable for a short storage time of 10 nanoseconds, and then successfully shuttled the information to a second qubit.
"We tested a new element for quantum information systems," says NIST physicist Ray Simmonds. "It's really significant because it means we can couple more qubits together and transfer information between them easily using one simple element."
The NIST work, together with another letter in the same issue of Nature by a Yale University group, is the first demonstration of a superconducting quantum bus. Whereas the NIST scientists used the bus to store and transfer information between independent qubits, the Yale group used it to enable an interaction of two qubits, creating a combined superposition state. These three actions, demonstrated collectively by the two groups, are essential for performing the basic functions needed in a superconductor-based quantum information processor of the future.
In addition to storing and transferring information, NIST's resonant cable also offers a means of "refreshing" superconducting qubits, which normally can maintain the same delicate quantum state for only half a microsecond. Disturbances such as electric or magnetic noise in the circuit can rapidly destroy a qubit's superposition state. With design improvements, the NIST technology might be used to repeatedly refresh the data and extend qubit lifetime more than 100-fold, sufficient to create a viable short-term quantum computer memory, Simmonds says. NIST's resonant cable might also be used to transfer quantum information between matter and light -- microwave energy is a low-frequency form of light -- and thus link quantum computers to ultra-secure quantum communications systems.
If they can be built, quantum computers -- harnessing the unusual rules of quantum mechanics, the principles governing nature's smallest particles -- might be used for applications such as fast and efficient code breaking, optimizing complex systems such as airline schedules, making counterfeit-proof money, and solving complex mathematical problems. Quantum information technology in general allows for custom-designed systems for fundamental tests of quantum physics and as-yet-unknown futuristic applications.
A superconducting qubit is about the width of a human hair. NIST researchers fabricate two qubits on a sapphire microchip, which sits in a shielded box about 8 cubic millimeters in size. The resonant section of cable is 7 millimeters long, similar to the coaxial wiring used in cable television but much thinner and flatter, zig-zagging around the 1.1 mm space between the two qubits. Like a guitar string, the resonant cable can be stimulated so that it hums or "resonates" at a particular tone or frequency in the microwave range. Quantum information is stored as energy in the form of microwave particles or photons.
The NIST research was supported in part by the Disruptive Technology Office.
*M.A. Sillanpää, J.I. Park, and R.W. Simmonds. 2007. Coherent quantum state storage and transfer between two phase qubits via a resonant cavity. Nature, Sept. 27.
Note: This story has been adapted from a news release issued by National Institute of Standards and Technology.

Fausto Intilla

www.oloscience.com

Computer Memory Designed In Nanoscale Can Retrieve Data 1,000 Times Faster

Source:

http://www.sciencedaily.com/releases/2007/09/070917115319.htm

Science Daily — Scientists from the University of Pennsylvania have developed nanowires capable of storing computer data for 100,000 years and retrieving that data a thousand times faster than existing portable memory devices such as Flash memory and micro-drives, all using less power and space than current memory technologies.
Ritesh Agarwal, an assistant professor in the Department of Materials Science and Engineering, and colleagues developed a self-assembling nanowire of germanium antimony telluride, a phase-changing material that switches between amorphous and crystalline structures, the key to read/write computer memory. Fabrication of the nanoscale devices, roughly 100 atoms in diameter, was performed without conventional lithography, the blunt, top-down manufacturing process that employs strong chemicals and often produces unusable materials with space, size and efficiency limitations.
Instead, researchers used self-assembly, a process by which chemical reactants crystallize at lower temperatures mediated by nanoscale metal catalysts to spontaneously form nanowires that were 30-50 nanometers in diameter and 10 micrometers in length, and then they fabricated memory devices on silicon substrates.
"We measured the resulting nanowires for write-current amplitude, switching speed between amorphous and crystalline phases, long-term durability and data retention time," Agarwal said.
Tests showed extremely low power consumption for data encoding (0.7mW per bit). They also indicated the data writing, erasing and retrieval (50 nanoseconds) to be 1,000 times faster than conventional Flash memory and indicated the device would not lose data even after approximately 100,000 years of use, all with the potential to realize terabit-level nonvolatile memory device density.
"This new form of memory has the potential to revolutionize the way we share information, transfer data and even download entertainment as consumers," Agarwal said. "This represents a potential sea-change in the way we access and store data."
Phase-change memory in general features faster read/write, better durability and simpler construction compared with other memory technologies such as Flash. The challenge has been to reduce the size of phase change materials by conventional lithographic techniques without damaging their useful properties. Self-assembled phase-change nanowires, as created by Penn researchers, operate with less power and are easier to scale, providing a useful new strategy for ideal memory that provides efficient and durable control of memory several orders of magnitude greater than current technologies.
"The atomic scale of the nanodevices may represent the ultimate size limit in current-induced phase transition systems for non-volatile memory applications," Agarwal said.
Current solid-state technology for products like memory cards, digital cameras and personal data assistants traditionally utilize Flash memory, a non-volatile and durable computer memory that can be erased and reprogrammed electronically. Data on Flash drives provides most battery-powered devices with acceptable levels of durability and moderately fast data access. Yet the technology's limits are apparent. Digital cameras can't snap rapid-fire photos because it takes precious seconds to store the last photo to memory. If the memory device is fast, as in DRAM and SRAM used in computers, then it is volatile; if the plug on a desktop computer is pulled, all recent data entry is lost.
Therefore, a universal memory device is desired that can be scalable, fast, durable and nonvolatile, a difficult set of requirements which have now been demonstrated at Penn.
"Imagine being able to store hundreds of high-resolution movies in a small drive, downloading them and playing them without wasting time on data buffering, or imagine booting your laptop computer in a few seconds as you wouldn't need to transfer the operating system to active memory" Agarwal said.
The research was performed by Agarwal, Se-Ho Lee and Yeonwoong Jung of the Department of Materials Science and Engineering in the School of Engineering and Applied Science at Penn. The findings appear online in the journal Nature Nanotechnology and in the October print edition.
The research was supported by the Materials Research Science and Engineering Center at Penn, the University of Pennsylvania Research Foundation award and a grant from the National Science Foundation.
Note: This story has been adapted from a news release issued by University of Pennsylvania.

Fausto Intilla
www.oloscience.com

NCAR Adds Resources To TeraGrid

Source:

http://www.sciencedaily.com/releases/2007/08/070810194742.htm

Science Daily — Researchers who use the TeraGrid, the nation's most comprehensive and advanced infrastructure for open scientific research, can now leverage the computing resources of a powerful, 2048-processor BlueGene/L system at the National Center for Atmospheric Research (NCAR).

NCAR plans to provide up to 4.5 million processor-hours of BlueGene/L computing annually to researchers who have received computing grants from the National Science Foundation (NSF).The operational integration of TeraGrid with the BlueGene/L system, nicknamed "frost," involved extensive preparation by NCAR's Computational and Information Systems Laboratory (CISL). Engineers deployed the necessary networking infrastructure, then established connectivity to NCAR's data storage systems, and merged the local resource accounting system with the TeraGrid. "We are excited to be at a point where all our hard work and preparation pays off, and to provide the TeraGrid community with access to this valuable collaborative resource," says Richard Loft, NCAR TeraGrid principal investigator. NCAR is also testing experimental systems and services on the TeraGrid. These include the wide-area versions of general parallel file systems from IBM and Cluster File Systems, as well as a remote data visualization capability based on the VAPOR tool, an open source application developed by NCAR, the University of California, Davis, and Ohio State University under the sponsorship of NSF.NCAR's frost system, which is operated in partnership with the University of Colorado, will be the second BlueGene/L system on the TeraGrid, joining the San Diego Supercomputer Center's 6,144 processor system. With the addition of frost, the TeraGrid has more than 250 teraflops of computing capability and more than 30 petabytes of online and archival data storage, with rapid access and retrieval over high-performance networks.About the TeraGridThe TeraGrid, sponsored by the National Science Foundation Office of Cyberinfrastructure, is a partnership of people, resources, and services that enables discovery in U.S. science and engineering. Through coordinated policy, grid software, and high-performance network connections, the TeraGrid integrates a distributed set of high-capability computational, data-management and visualization resources to make research more productive.

Note: This story has been adapted from a news release issued by National Center for Atmospheric Research.

Fausto Intilla

www.oloscience.com