Group items tagged

In Stack Machines, Expression Evaluation, and the Magic of Reverse Polish, I showed how expressions can be evaluated by rewriting them in reverse Polish and translating this into machine-code instructions for a stack machine. I demonstrated with a stack-machine interpreter that I'd written as part of a working model of a Pascal compiler. But as well as expressions, the compiler needs to compile assignments and jumps, so — in my progress towards explaining the compiler — I'm going to extend the machine code so it can handle these. I'll demonstrate by interpreting a program that calculates five factorial.

Japan’s National Institute of Advanced Industrial Science and Technology (AIST) has detailed the software used to make their robot dance (see some nice photos over at Pink Tentacle) in a recent press release.  The software, dubbed Choreonoid (Choreography and Humanoid), is similar to conventional computer animation software.  Users create key poses and the software automatically interpolates the motion between them.  What makes the software unique is that it also corrects the poses if they are mechanically unstable, such as modifying the position of the feet and waist, allowing anyone to create motions compatible with the ZMP balancing method.  This is especially important for robots like the HRP-4C, where complicated motions could easily cause it to fall over.

South Korean researchers have recently made a flexible nonvolatile memory based on memristors—fundamental electronic circuit elements discovered in 2008—using thin graphene oxide films. Memristors promise a new type of dense, cheap, and low-power memory and have typically been made using metal oxide thin films. The new graphene oxide devices should be cheaper and simpler to fabricate—they could be printed on rolls of plastic sheets and used in plastic RFID tags or in the wearable electronics of the future. "We think graphene oxide can be a good candidate for next-generation memory," says Sung-Yool Choi, who leads flexible devices research at the Electronics and Telecommunications Research Institute in Daejeon, South Korea. Choi and his colleagues reported their device last week in Nano Letters.

Even in sleep, the human body is rarely still—and within it, there is the constant motion of the contents of our cells and the proteins within. Until now, scientists have had to estimate the speed of complex but common actions such as protein folding (which turns an unorganized polypeptide strand into a complex and useful three-dimensional protein). They could watch the action unfold, so to speak, in a test tube but weren’t sure how close the pace conformed to real life. A group of researchers at the University of Illinois at Urbana–Champaign, however, have developed a system to move the observation out of in vitro and into in vivo.

Andrew Phillips holds the title of Scientist with Microsoft Research Cambridge, and he's working on a method of programming that compiles into DNA. Part of this involves a visual programming language called Stochastic Pi Machine, or SPiM. This system models biological processes to help give researchers feedback on how organisms will react to modifications. The hope is that this can be used to help scientists program for large biological systems using modular components compiled to DNA. Yes, I’m in way over my head here, but I do my best to ask Andrew about the role this will play in medical treatment going forward, what it means to DNA computing, and the ability of back-engineering the genetic code we don’t use now

Commenter Cynox was browsing through the 137 years of Popular Science magazine which are now available online, and he noticed this robot in the September 1984 issue. Called Odex I, it was developed by a (now apparently defunct) company called Odetics. Odex was six and a half feet tall, had six legs, and was fully capable of walking. Although it only weighed 370 pounds, each of its legs could lift 400 pounds. It could dead lift some 2100 pounds, and carry 900 pounds while walking at normal speed (which was about 18 inches per second). Odex used a tripod gait, and the fishbowl thing on top contained sensors that helped it avoid obstacles. It was one of the first robots with an onboard computer that helped coordinate all of its limbs. Since the limbs could articulate themselves in several directions independently, Odex was able to rapidly change its limb configuration to squeeze through tight spaces, move quickly, or lift stuff. It was able to climb into the back of a truck through a combination of automated step behaviors and teleoperation, which was pretty damn good for 1984.

I remember when, a decade ago, Kevin Warwick, a professor at the University of Reading, in the U.K., implanted a radio chip in his own arm. The feat caused quite a stir. The implant allowed him to operate doors, lights, and computers without touching anything. On a second version of the project he could even control an electric wheelchair and produce artificial sensations in his brain using the implanted chip. Warwick had become, in his own words, a cyborg. The idea of a cyborg -- a human-machine hybrid -- is common in science fiction and although the term dates back to the 1960s it still generates a lot of curiosity. I often hear people asking, When will we become cyborgs? When will humans and machines merge? Although some researchers might have specific time frames in mind, I think a better answer is: It's already happening. When we look back at the history of technology, we tend to see distinct periods -- before the PC and after the PC, before the Internet and after the Internet, and so forth -- but in reality most technological advances unfold slowly and gradually. That's particularly true with the technologies that are allowing us to modify and enhance our bodies.

March has seen two significant announcements from FPGA start-ups with innovative architectures: Tabula, with their time-domain-multiplexed architecture, and TierLogic, implementing their routing switches in a layer of thin-film transistors. Both approaches promise to significantly reduce the die size and cost of high-end FPGAs. But before these announcements broke, a relatively unnoticed paper at February's International Symposium on FPGAs described what may be the most radical technology of them all: FPGAs using electromechanical relays. No, this is not an early April Fool's joke, nor is it one of those "let's see if anyone will publish this one" academic exercises. The paper presented work by professors and students at the Stanford University departments of electrical engineering and computer science, and researchers at Altera Corp. The work was supported in part by DARPA funding.

The moving parts of micromechanical machines tend to seize up under the forces of sticking and friction that engineers call stiction. The problem yields to solid lubricants, notably graphite (sheets of carbon atoms called graphene stacked in layers), although for a long time no one understood exactly why this happens. Now nanotechnology researchers, led by Professor Robert Carpick at the University of Pennsylvania and Professor James Hone at Columbia University, in New York City, have shown that how effective the lubrication is depends on the number of layers of graphene in the graphite. In particular, more layers means better lubrication. Because the same relationship between layers and lubrication occurs in thin sheets of molybdenum disulfide, niobium diselenide, and boron nitride—materials of widely differing properties—the workers conclude that this behavior is a fundamental aspect of friction. They expect that the discovery will lead to better lubrication of tiny moving parts. The researchers published details of their experiments in a recent issue of Science.

One of the biggest commercial applications of spintronics in computing to date has been the use of giant magnetoresistance (GMR), the material phenomenon that makes possible the huge storage capacity of today’s hard disk drives. In the awarding of the 2007 Nobel Prize in Physics, GMR was cited as the first big commercial application for nanotechnology. But extending the commercial application of spintronic-enabled systems beyond read heads for HDDs has proven to be a difficult task. One need only look at the seemingly endless travails of NVE Corporation, which in its financial results still shows it greatest revenue growth in contract research as opposed to product sales. While recent research from a team of researchers at Ohio State University and the University of Hamburg in Germany may not turn around the fortunes of spintronics in the short term, it does provide a way to better characterize the spin of electrons and thereby promises better ways of exploiting it for electronics applications. The researchers are reporting in Nature Nanotechnology that they have for the first time been able to create images of the spin direction of electrons.

With the GA release of Scala 2.8 getting very close, David Pollak, the creator of the Scala-based web framework: Lift, has announced a Scala community initiative that  will have an equally large impact on Scala developers.  The Fresh Scala Initiative aims to address the issue of version fragility in the ecosystem.  You may have heard that Scala 2.8 is not binary compatible with the 2.7 branch.  Therefore, some community members have banded together to maintain a repository and provide nightly builds of popular Scala library collections to build against Scala 2.8.  

F# is ideal for data-rich, concurrent and algorithmic development: "simple code to solve complex problems". F# is a simple and pragmatic programming language combining functional, object-oriented and scripting programming, and supports cross-platform environments including PC, Mac, and Linux. We'll provide the tutorials, resources and tools you’ll need to begin working with F# right away.

Researchers at the Institute for Logic, Language and Computation (ILLC) of the University of Amsterdam have discovered a universal property of musical scales. Until now it was assumed that the only thing scales throughout the world have in common is the octave.

People have been using pens to jot down their thoughts for thousands of years but now engineers at the University of Illinois have developed a silver-inked rollerball pen that allows users to jot down electrical circuits and interconnects on paper, wood and other surfaces. Looking just like a regular ballpoint pen, the pen's ink consists of a solution of real silver that dries to leave electrically conductive silver pathways. These pathways maintain their conductivity through multiple bends and folds of the paper, enabling users to personally fabricate low-cost, flexible and disposable electronic devices. While metallic inks have been used to manufacture electronic devices using inkjet printing technology, the silver pen offers users the freedom and flexibility to construct electronic devices on the fly, says Jennifer Lewis, the Hans Thurnauer professor of materials science and engineering at the University of Illinois who led the research team along with Jennifer Bernhard, a professor of electrical and computer engineering.