OpenSim open-source software from Stanford accurately models human motion

 by Biomechanism 

(Biomechanism) — In a new exhibit at The Leonardo, a science and technology museum in Salt Lake City, a team of Stanford engineers is demonstrating an open source software package called OpenSim that accurately models human movement. OpenSim is free and in use across the world helping scientists understand the complex forces of movement to improve diagnosis of physical disabilities and prevent harmful wear and tear.

There are 640 muscles in the human body, or maybe it is 639. Or maybe it is 850. Or 656. It all depends on whom you ask. In any case, it is a lot. Stanford bioengineer Scott Delp knows; he has programmed almost every one into his latest work, OpenSim, a software application that helps medical professionals and bioengineers study, diagnose and correct abnormalities in how people move.

In the legs alone there are more than 100 muscles, virtually every one necessary to maintain balance and walk properly. Most of us take these for granted; they just work. But for some, they don’t. Scott Delp, a professor of bioengineering, mechanical engineering and orthopedic surgery, helps these people.

And now, OpenSim will be on display at The Leonardo, a science and technology museum in Salt Lake City. OpenSim is part of an exhibit exploring human movement.

More than child’s play

The idea to unite museum and modeling software was the brainchild of Andy Anderson, a research assistant professor at the University of Utah School of Medicine. He was a visiting scholar working with Delp and Jennifer Hicks over the summer and he put the pieces together to get OpenSim involved with the exhibit in his hometown, Salt Lake City.

The Leonardo exhibit is really two exhibits in one. In the first section, visitors walk across a pressure-sensitive floor and are presented at the other side with color-coded print outs of their weight distribution, identifying even slight imbalances that might be putting undue stress on their limbs and joints. Such stress can lead to pain or arthritis. Over a lifetime, even relatively minor abnormalities can compound until hip and knee replacement surgeries become necessary.

“This one is fun because people can insert various orthotics in their shoes and see how they affect their movement. It’s quite telling,” said Anderson.

The second exhibit is aimed at kids. To make their research more approachable for a younger audience, the OpenSim development team is creating an interactive soccer game. The real-world player adjusts the strength of two leg muscles on the simulated soccer player to generate the force necessary to kick a virtual ball into a virtual goal.

“This is a simplified version of our software, but by honing things down to just two muscles we can make the science of movement something kids can understand and have fun with,” said Hicks, a mechanical engineer and the OpenSim project manager at Stanford. “Most importantly, it is based on real physics and realistic physiology, so it really teaches as it entertains.”

“Human movement is incredibly complex,” said Hicks. “The kids’ first instinct is to crank up the muscles to full strength, but this has unintended consequences, as the kids quickly learn.”

Profound implications

Future possibilities for OpenSim are many. It can help determine whether a simple surgery to lengthen a specific muscle might help victims of cerebral palsy. It can predict how simple changes in gait might reduce the incidence or severity of osteoarthritis. In addition to helping millions delay or avoid costly hip and knee replacements, OpenSim could help in the development of new, more sensitive prosthetics, able to read and interpret electrical impulses to control the devices.

For all its technical wizardry, however, the greatest fact about OpenSim may be that it is open source. Anyone with a computer and an Internet connection can have the software in a matter of minutes. Delp is giving it away.

“OpenSim is out there and hundreds are downloading it every week,” said Hicks. “If each copy helps only one person, that’s helping a lot of people.”

“That’s the exciting thing about open source,” said Delp. “By putting this powerful software in the hands of as many people as possible, we are setting in motion a self-perpetuating research ecosystem that will build upon itself to push the field forward.”

New Hybrid Technology Could Bring 'Quantum Information Systems'

Science Daily — The merging of two technologies under development -- plasmonics and nanophotonics -- is promising the emergence of new "quantum information systems" far more powerful than today's computers.

The technology hinges on using single photons -- the tiny particles that make up light -- for switching and routing in future computers that might harness the exotic principles of quantum mechanics.

The quantum information processing technology would use structures called "metamaterials," artificial nanostructured media with exotic properties.

The metamaterials, when combined with tiny "optical emitters," could make possible a new hybrid technology that uses "quantum light" in future computers, said Vladimir Shalaev, scientific director of nanophotonics at Purdue University's Birck Nanotechnology Center and a distinguished professor of electrical and computer engineering.

The concept is described in an article published on October 28 in the journal Science. The article appeared in the magazine's Perspectives section and was written by Shalaev and Zubin Jacob, an assistant professor of electrical and computer engineering at the University of Alberta, Canada.

"A seamless interface between plasmonics and nanophotonics could guarantee the use of light to overcome limitations in the operational speed of conventional integrated circuits," Shalaev said.

Researchers are proposing the use of "plasmon-mediated interactions," or devices that manipulate individual photons and quasiparticles called plasmons that combine electrons and photons.

One of the approaches, pioneered at Harvard University, is a tiny nanowire that couples individual photons and plasmons. Another approach is to use hyperbolic metamaterials, suggested by Jacob; Igor Smolyaninov, a visiting research scientist at the University of Maryland; and Evgenii Narimanov, an associate professor of electrical and computer engineering at Purdue. Quantum-device applications using building blocks for such hyperbolic metamaterials have been demonstrated in Shalaev's group.

"We would like to record and read information with single photons, but we need a very efficient source of single photons," Shalaev said. "The challenge here is to increase the efficiency of generation of single photons in a broad spectrum, and that is where plasmonics and metamaterials come in."

Today's computers work by representing information as a series of ones and zeros, or binary digits called "bits."

Computers based on quantum physics would have quantum bits, or "qubits," that exist in both the on and off states simultaneously, dramatically increasing the computer's power and memory. Quantum computers would take advantage of a strange phenomenon described by quantum theory called "entanglement." Instead of only the states of one and zero, there are many possible "entangled quantum states" in between one and zero.

An obstacle in developing quantum information systems is finding a way to preserve the quantum information long enough to read and record it. One possible solution might be to use diamond with "nitrogen vacancies," defects that often occur naturally in the crystal lattice of diamonds but can also be produced by exposure to high-energy particles and heat.

"The nitrogen vacancy in diamond operates in a very broad spectral range and at room temperature, which is very important," Shalaev said.

The work is part of a new research field, called diamond photonics. Hyperbolic metamaterials integrated with nitrogen vacancies in diamond are expected to work as efficient "guns" of single photons generated in a broad spectral range, which could bring quantum information systems, he said.

Law of nature refuted

SWINBURNE UNIVERSITY OF TECHNOLOGY

The so-called fine-structure constant, denoted by the symbol ‘alpha' - seems to vary across the Universe. Image: catscandotcom/iStockphoto One of the laws of nature may vary across the Universe, according to a study published today in the journal Physical Review Letters. One of the most cherished principles in science - the constancy of physics - may not be true, according to research carried out at the University of New South Wales (UNSW), Swinburne University of Technology and the University of Cambridge. The study found that one of the four known fundamental forces, electromagnetism - measured by the so-called fine-structure constant and denoted by the symbol ‘alpha' - seems to vary across the Universe. The first hints that alpha might not be constant came a decade ago when Professor John Webb, Professor Victor Flambaum, and other colleagues at UNSW and elsewhere, analysed observations from the Keck Observatory, in Hawaii. Those observations were restricted to one broad area in the sky. However, now Webb and colleagues (PhD graduate Dr Julian King, PhD student Matthew Bainbridge and Professor Victor Flambaum at UNSW; Dr Michael Murphy at Swinburne University of Technology, and Professor Bob Carswell from Cambridge University) have doubled the number of observations and measured the value of alpha in about 300 distant galaxies, all at huge distances from Earth, and over a much wider area of the sky. The new observations were obtained using the European Southern Observatory's ‘Very Large Telescope' in Chile. "The results astonished us," said Professor Webb. "In one direction - from our location in the Universe - alpha gets gradually weaker, yet in the opposite direction it gets gradually stronger." "The discovery, if confirmed, has profound implications for our understanding of space and time and violates one of the fundamental principles underlying Einstein's General Relativity theory," Dr King added. "Such violations are actually expected in some more modern ‘Theories of Everything' that try to unify all the known fundamental forces," said Professor Flambaum. "The smooth continuous change in alpha may also imply the Universe is much larger than our observable part of it, possibly infinite." "Another currently popular idea is that many universes exist, each having its own set of physical laws," Dr Murphy said. "Even a slight change in the laws of Nature means they weren't ‘set in stone' when our Universe was born. The laws of Nature you see may depend on your ‘space-time address' - when and where you happen to live in the Universe." Professor Webb said these new findings also offer a very natural explanation for a question that puzzled scientists for decades: why do the laws of physics seem to be so finely-tuned for the existence of life? "The answer may be that other regions of the Universe are not quite so favourable for life as we know it, and that the laws of physics we measure in our part of the Universe are merely ‘local by-laws', in which case it is no particular surprise to find life here," he said. Editor's Note: Original news release can be found here.