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

Technology Could Enable Computers To 'Read The Minds' Of Users

Source:

http://www.sciencedaily.com/releases/2007/10/071001125649.htm

Science Daily — Tufts University researchers are developing techniques that could allow computers to respond to users' thoughts of frustration -- too much work -- or boredom--too little work. Applying non-invasive and easily portable imaging technology in new ways, they hope to gain real-time insight into the brain's more subtle emotional cues and help provide a more efficient way to get work done.
"New evaluation techniques that monitor user experiences while working with computers are increasingly necessary," said Robert Jacob, computer science professor and researcher. "One moment a user may be bored, and the next moment, the same user may be overwhelmed. Measuring mental workload, frustration and distraction is typically limited to qualitatively observing computer users or to administering surveys after completion of a task, potentially missing valuable insight into the users' changing experiences."
Sergio Fantini, biomedical engineering professor, in conjunction with Jacob's human-computer interaction (HCI) group, is studying functional near-infrared spectroscopy (fNIRS) technology that uses light to monitor brain blood flow as a proxy for workload stress a user may experience when performing an increasingly difficult task. A $445,000 grant from the National Science Foundation will allow the interdisciplinary team to incorporate real-time biomedical data with machine learning to produce a more in-tune computer user experience.
Lighting up the brain
"fNIRS is an emerging non-invasive, lightweight imaging tool which can measure blood oxygenation levels in the brain," said Fantini, also an associate dean for graduate education at Tufts' School of Engineering.
The fNIRS device, which looks like a futuristic headband, uses laser diodes to send near-infrared light through the forehead at a relatively shallow depth--only two to three centimeters--to interact with the brain's frontal lobe. Light usually passes through the body's tissues, except when it encounters oxygenated or deoxygenated hemoglobin in the blood. Light waves are absorbed by the active, blood-filled areas of the brain and any remaining light is diffusely reflected to the fNIRS detectors.
"fNIRS, like MRI, uses the idea that blood flow changes to compensate for the increased metabolic demands of the area of the brain that's being used," said Erin Solovey, a graduate researcher at the School of Engineering.
"We don't know how specific we can be about identifying users' different emotional states," said Fantini. "However, the particular area of the brain where the blood flow change occurs should provide indications of the brain metabolic changes and by extension workload, which could be a proxy for emotions like frustration."
In the initial experiments, Jacob and Fantini's groups determined how accurately fNIRS could register users' workload. While wearing the fNIRS device, test subjects viewed a multicolored cube consisting of eight smaller cubes with two, three or four different colors. As the cube rotated onscreen, subjects counted the number of colored squares in a series of 30 tasks. The fNIRS device and subsequent user surveys reflected greater difficulty as users kept track of increasing numbers of colors. The fNIRS data agreed with user surveys up to 83 percent of the time.
The Tufts group will present its initial results on using fNIRS to detect the user workload experience at the Association for Computing Machinery (ACM) symposium on user interface software and technology, to be held Oct. 7 through 10 in Newport, R.I.
"It seems that we can predict, with relatively high confidence, whether the subject was experiencing no workload, low workload, or high workload," said Leanne Hirshfield, a graduate researcher and lead author on the poster paper to be presented at the ACM symposium.
Note: This story has been adapted from material provided by Tufts University.

Fausto Intilla
www.oloscience.com

Any Digital Camera Can Take Multibillion-pixel Shots With New Device

Source:

http://www.sciencedaily.com/releases/2007/09/070926111630.htm

Science Daily — Researchers at Carnegie Mellon University, in collaboration with scientists at NASA's Ames Research Center, have built a low-cost robotic device that enables any digital camera to produce breathtaking gigapixel (billions of pixels) panoramas, called GigaPans.

The technology gives people a new way to make and share images of their environment. It is being used by students to document their communities and by the Commonwealth of Pennsylvania to make Civil War sites accessible on the Web. To promote further sharing of this imagery, Carnegie Mellon has launched a public Web site, http://www.gigapan.org/, where people can upload and interactively explore panoramic images of any format.
In cooperation with Google, researchers also have created a GigaPan layer on Google Earth. Anyone using Google Earth can now fly into these GigaPan panoramas in the context of exploring the world.
Researchers have begun a public beta process with the GigaPan hardware, Web site, and software. The hardware technology enabling GigaPan images is a robotic camera mount, jointly designed and manufactured by Charmed Labs of Austin Texas. The tripod-like mount makes it possible for a digital camera to take hundreds of overlapping images of landscapes, buildings or rooms. Then, using software developed by Carnegie Mellon and Ames, these images can be arranged in a grid and digitally stitched together into a single image that could consist of tens of billions of pixels.
These huge image files can then be explored by zooming in on features of interest in a manner similar to Google Earth. "We have taken imagery and made it a new tool for exploration and for enhancing global understanding," said Illah Nourbakhsh, associate professor in the School of Computer Science's Robotics Institute. Nourbakhsh and Randy Sargent, senior systems scientist at Carnegie Mellon West in Moffett Field, Calif., led GigaPan's development. "An ordinary photo makes it possible to cross language barriers," Nourbakhsh explained. "But a GigaPan provides so much information that it leads to conversations between the person who took the panoramas and the people who are exploring it and discovering new details."
Last spring, the Pennsylvania Board of Tourism began to use GigaPan to enable people to virtually explore Civil War sites. The technology is also being used for Robot250, an arts-based robotics program in the Pittsburgh area. Robot250 will increase technical literacy by teaching students, artists and other members of the public how to build customized robots.
Nourbakhsh and his colleagues recently began to work with UNESCO's International Bureau of Education and its Associated Schools Network on a project that will link school children in different parts of the world in exploring issues of cultural identity through a classroom project. Middle school children from Pittsburgh to South Africa to Trinidad and Tobago will use the GigaPan camera to share images of their neighborhoods, lives and cultures. "This project will explore curriculum development from the local to the global level," said IBE Director Clementina Acedo.
"It is an extraordinary opportunity to link a school-community based educational practice with high-end technology in the service of children's innovative learning, personal development and world communication. Plans call for the experiences of these children from poorer and richer countries to be presented at the 48th session of the International Conference of Education scheduled to take place in Geneva in November 2008.
Besides being a tool for education, Nourbakhsh and Sargent see the GigaPan system as an important tool for ecologists, biologists and other scientists. They plan to foster this effort by making several dozen GigaPans available to leading scientists with support from the Fine Foundation of Pittsburgh.
Nourbakhsh hopes the non-commercial GigaPan site will help to develop a community of GigaPan producers and users. "We're not interested in becoming just another photo-sharing site," he said. "We want as many people as possible involved. GigaPan is not just about the vision of the person who makes the image. People who explore the image can make discoveries and gain insights in ways that may be just as important."
Sargent got the idea for GigaPan when he was a technical staff member at Ames Research Center, helping to develop software for combining images from NASA's Mars Exploration Rovers into panoramas. He became convinced that the same technology could open people's eyes to the diversity of their own planet. "It is increasingly important to give people a broad view of the world, particularly to help us understand different cultures and different environments," he said. "It's too easy to have blinders on and to only see and understand what is local."
The GigaPan camera system is part of a larger effort known as the Global Connection Project, led by Nourbakhsh and Sargent. Its purpose is to make people all over the world more aware of their neighbors.
Note: This story has been adapted from material provided by Carnegie Mellon University.

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

Two Giant Steps In Advancement Of Quantum Computing Achieved

Source:

http://www.sciencedaily.com/releases/2007/09/070926172350.htm

Science Daily — Two major steps toward putting quantum computers into real practice -- sending a photon signal on demand from a qubit onto wires and transmitting the signal to a second, distant qubit -- have been brought about by a team of scientists at Yale.

The accomplishments are reported in sequential issues of Nature on September 20 and September 27, on which it is highlighted as the cover along with complementary work from a group at the National Institute of Standards and Technologies.
Over the past several years, the research team of Professors Robert Schoelkopf in applied physics and Steven Girvin in physics has explored the use of solid-state devices resembling microchips as the basic building blocks in the design of a quantum computer. Now, for the first time, they report that superconducting qubits, or artificial atoms, have been able to communicate information not only to their nearest neighbor, but also to a distant qubit on the chip.
This research now moves quantum computing from "having information" to "communicating information." In the past information had only been transferred directly from qubit to qubit in a superconducting system. Schoelkopf and Girvin's team has engineered a superconducting communication 'bus' to store and transfer information between distant quantum bits, or qubits, on a chip. This work, according to Schoelkopf, is the first step to making the fundamentals of quantum computing useful.
The first breakthrough reported is the ability to produce on demand -- and control -- single, discrete microwave photons as the carriers of encoded quantum information. While microwave energy is used in cell phones and ovens, their sources do not produce just one photon. This new system creates a certainty of producing individual photons.
"It is not very difficult to generate signals with one photon on average, but, it is quite difficult to generate exactly one photon each time. To encode quantum information on photons, you want there to be exactly one," according to postdoctoral associates Andrew Houck and David Schuster who are lead co-authors on the first paper.
"We are reporting the first such source for producing discrete microwave photons, and the first source to generate and guide photons entirely within an electrical circuit," said Schoelkopf.
In order to successfully perform these experiments, the researchers had to control electrical signals corresponding to one single photon. In comparison, a cell phone emits about 10^23 (100,000,000,000,000,000,000,000) photons per second. Further, the extremely low energy of microwave photons mandates the use of highly sensitive detectors and experiment temperatures just above absolute zero.
"In this work we demonstrate only the first half of quantum communication on a chip -- quantum information efficiently transferred from a stationary quantum bit to a photon or 'flying qubit,'" says Schoelkopf. "However, for on-chip quantum communication to become a reality, we need to be able to transfer information from the photon back to a qubit."
This is exactly what the researchers go on to report in the second breakthrough. Postdoctoral associate Johannes Majer and graduate student Jerry Chow, lead co-authors of the second paper, added a second qubit and used the photon to transfer a quantum state from one qubit to another. This was possible because the microwave photon could be guided on wires -- similarly to the way fiber optics can guide visible light -- and carried directly to the target qubit. "A novel feature of this experiment is that the photon used is only virtual," said Majer and Chow, "winking into existence for only the briefest instant before disappearing."
To allow the crucial communication between the many elements of a conventional computer, engineers wire them all together to form a data "bus," which is a key element of any computing scheme. Together the new Yale research constitutes the first demonstration of a "quantum bus" for a solid-state electronic system. This approach can in principle be extended to multiple qubits, and to connecting the parts of a future, more complex quantum computer.
However, Schoelkopf likened the current stage of development of quantum computing to conventional computing in the 1950's, when individual transistors were first being built. Standard computer microprocessors are now made up of a billion transistors, but first it took decades for physicists and engineers to develop integrated circuits with transistors that could be mass produced.
Schoelkopf and Girvin are members of the newly formed Yale Institute for Nanoscience and Quantum Engineering (YINQE), a broad interdisciplinary activity among faculty and students from across the university.
Other Yale authors involved in the research are J.M. Gambetta, J.A. Schreier, J. Koch, B.R. Johnson, L. Frunzio, A. Wallraff, A. Blais and Michel Devoret. Funding for the research was from the National Security Agency under the Army Research Office, the National Science Foundation and Yale University.
Citation: Nature 449, 328-331 (20 September 2007) doi:10.1038/nature06126 , Nature 450, 443-447 (27 September 2007) doi:10.1038/nature06184
Note: This story has been adapted from a news release issued by Yale University.

Fausto Intilla

www.oloscience.com

'Printers' That Can Make 3-D Solid Objects Soon To Enter Mainstream

Source:

http://www.sciencedaily.com/releases/2007/09/070925081418.htm

Science Daily — It is a simple matter to print an E-book or other document directly from your computer, whether that document is on your hard drive, at a web site or in an email. But, imagine being able to 'print' solid objects, a piece of sports equipment, say, or a kitchen utensil, or even a prototype car design for wind tunnel tests. US researchers suggest such 3-D printer technology will soon enter the mainstream once a killer application emerges.
Such technology already exists and is maturing rapidly so that high-tech designers and others can share solid designs almost as quickly as sending a fax. The systems available are based on bath of liquid plastic which is solidified by laser light. The movements of the laser are controlled by a computer that reads a digitized 3D map of the solid object or design.
Writing in the Inderscience publication International Journal of Technology Marketing, US researchers discuss how this technology might eventually move into the mainstream allowing work environments to 3-D print equipment, whether that is plastic paperclips, teacups, or components that can be joined to make sophisticated devices, perhaps bolted together with printed nuts and bolts.
Physicist Phil Anderson of the School of Theoretical and Applied Science working with Cherie Ann Sherman of the Anisfield School of Business, both at Ramapo College of New Jersey, in Mahwah, New Jersey, explain how this technology, which is known formally as 'rapid prototyping' could revolutionize the way people buy goods.
It will allow them to buy or obtain a digital file representing a physical product electronically and then produce the object at a time and place convenient to them. The technology will be revolutionary in the same way that music downloads have shaken up the music industry. "This technology has the potential to generate a variety of new business models, which would enhance the average consumer's lifestyle," say the paper's authors.
The team discusses the current advanced applications of rapid prototyping which exist in the military where missing and damaged components can be produced at the site of action. Education too can make use of 3-D printing to allow students to make solid their experimental designs.
Also, product developers can share tangible prototypes by transferring the digitized design without the delay of shipping a solid object between sites, which may be separated by thousands of miles. The possibilities for consumer goods, individualized custom products, replacement components, and quick fixes for broken objects, are almost unlimited, the authors suggest.
From the business perspective, e-commerce sites will essentially become digital download sites with physical stores, retail employees, and shipping eliminated. It is only a matter of time before the 'killer application,' the 3-D equivalent of the mp3 music file, one might say, arrives to make owning a 3-D printer as necessary to the modern lifestyle as owning a microwave oven, a TV, or indeed a personal computer.
Note: This story has been adapted from a news release issued by Inderscience Publishers.

Fausto Intilla
www.oloscience.com