CAN OUR COMPUTERS CONTINUE TO GET SMALLER AND MORE POWERFUL?
University of Michigan computer scientist reviews frontier technologies to determine fundamental limits of computer scaling
From the FMS Global News Desk of Jeanne Hambleton University of Michigan August 2014
Algorithms help optimize the placement of parts on an Algorithms–a way to continue scaling. Advanced techniques such as “structured placement,” shown here and developed by Markov’s group, are currently being used to wring out optimizations in chip layout. Different circuit modules on an integrated circuit are shown in different colors. Algorithms for placement optimize both the locations and the shapes of modules; some nearby modules can be blended when this reduces the length of the connecting wires.Credit: Jin Hu, Myung-Chul Kim, Igor L. Markov (University of Michigan)
From their origins in the 1940s as sequestered, room-sized machines designed for military and scientific use, computers have made a rapid march into the mainstream, radically transforming industry, commerce, entertainment and governance while shrinking to become ubiquitous handheld portals to the world.
This progress has been driven by the industry’s ability to continually innovate techniques for packing increasing amounts of computational circuitry into smaller and denser microchips. But with miniature computer processors now containing millions of closely-packed transistor components of near atomic size, chip designers are facing both engineering and fundamental limits that have become barriers to the continued improvement of computer performance.
Have we reached the limits to computation?
In a review article in this week’s issue of the journal Nature, Igor Markov of the University of Michigan reviews limiting factors in the development of computing systems to help determine what is achievable, identifying “loose” limits and viable opportunities for advancements through the use of emerging technologies. His research for this project was funded in part by the National Science Foundation (NSF).
“Just as the second law of thermodynamics was inspired by the discovery of heat engines during the industrial revolution, we are poised to identify fundamental laws that could enunciate the limits of computation in the present information age,” says Sankar Basu, a program director in NSF’s Computer and Information Science and Engineering Directorate.
“Markov’s paper revolves around this important intellectual question of our time and briefly touches upon most threads of scientific work leading up to it.”
The article summarizes and examines limitations in the areas of manufacturing and engineering, design and validation, power and heat, time and space, as well as information and computational complexity.
“What are these limits, and are some of them negotiable? On which assumptions are they based? How can they be overcome?” asks Markov.
“Given the wealth of knowledge about limits to computation and complicated relations between such limits, it is important to measure both dominant and emerging technologies against them.”
Limits related to materials and manufacturing are immediately perceptible. In a material layer ten atoms thick, missing one atom due to imprecise manufacturing changes electrical parameters by ten percent or more. Shrinking designs of this scale further inevitably leads to quantum physics and associated limits.
Limits related to engineering are dependent upon design decisions, technical abilities and the ability to validate designs. While very real, these limits are difficult to quantify. However, once the premises of a limit are understood, obstacles to improvement can potentially be eliminated. One such breakthrough has been in writing software to automatically find, diagnose and fix bugs in hardware designs.
Limits related to power and energy have been studied for many years, but only recently have chip designers found ways to improve the energy consumption of processors by temporarily turning off parts of the chip. There are many other clever tricks for saving energy during computation. But moving forward, silicon chips will not maintain the pace of improvement without radical changes. Atomic physics suggests intriguing possibilities but these are far beyond modern engineering capabilities.
Limits relating to time and space can be felt in practice. The speed of light, while a very large number, limits how fast data can travel. Traveling through copper wires and silicon transistors, a signal can no longer traverse a chip in one clock cycle today. A formula limiting parallel computation in terms of device size, communication speed and the number of available dimensions has been known for more than 20 years, but only recently has it become important now that transistors are faster than interconnections. This is why alternatives to conventional wires are being developed, but in the meantime mathematical optimization can be used to reduce the length of wires by rearranging transistors and other components.
Several key limits related to information and computational complexity have been reached by modern computers. Some categories of computational tasks are conjectured to be so difficult to solve that no proposed technology, not even quantum computing, promises consistent advantage. But studying each task individually often helps reformulate it for more efficient computation.
When a specific limit is approached and obstructs progress, understanding the assumptions made is key to circumventing it. Chip scaling will continue for the next few years, but each step forward will meet serious obstacles, some too powerful to circumvent.
What about breakthrough technologies? New techniques and materials can be helpful in several ways and can potentially be “game changers” with respect to traditional limits. For example, carbon nanotube transistors provide greater drive strength and can potentially reduce delay, decrease energy consumption and shrink the footprint of an overall circuit.
On the other hand, fundamental limits–sometimes not initially anticipated–tend to obstruct new and emerging technologies, so it is important to understand them before promising a new revolution in power, performance and other factors.
“Understanding these important limits,” says Markov, “will help us to bet on the right new techniques and technologies.”
Principal Investigator was Igor Markov, University of Michigan,
The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering. In fiscal year (FY) 2014, its budget is $7.2 billion. NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and other institutions. Each year, NSF receives about 50,000 competitive requests for funding, and makes about 11,500 new funding awards. NSF also awards about $593 million in professional and service contracts yearly.
STUDY OF CHILEAN QUAKE SHOWS POTENTIAL FOR FUTURE EARTHQUAKE
From the FMS Global News Desk of Jeanne Hambleton National Science Foundation August 2014 By A’ndrea Elyse Messer
The Iquique earthquake took place on the northern portion of the subduction zone formed when the Nazca tectonic plate slides under the South American plate. Image: USGS
UNIVERSITY PARK, Pa. — Near real-time analysis of the April 1 earthquake in Iquique, Chile, showed that the 8.2 event occurred in a gap on the fault unruptured since 1877 and that the April event was not what the scientists had expected, according to an international team of geologists.
“We assumed that the area of the 1877 earthquake would eventually rupture, but all indications are that this 8.2 event was not the 8.8 event we were looking for,” said Kevin P. Furlong, professor of geophysics, Penn State.
“We looked at it to see if this was the big one.”
But according to the researchers, it was not. Seismologists expect that areas of faults will react the same way over and over. However, the April earthquake was about nine times less energetic than the one in 1877 and was incapable of releasing all the stress on the fault, leaving open the possibility of another earthquake.
The Iquique earthquake took place on the northern portion of the subduction zone formed when the Nazca tectonic plate slides under the South American plate. This is one of the longest uninterrupted plate boundaries on the planet and the site of many earthquakes and volcanos. The 8.2 earthquake was foreshadowed by a systematic sequence of foreshocks recorded at 6.0, 6.5, 6.7 and 6.2 with each foreshock triggering the next until the main earthquake occurred.
These earthquakes relieved the stresses on some parts of the fault. Then the 8.2 earthquake relieved more stress, followed by a series of aftershocks in the range of 7.7. While the aftershocks did fill in some of the gaps left by the 8.2 earthquake, the large earthquake and aftershocks could not fill in the entire gap where the fault had not ruptured in a very long time. That area is unruptured and still under stress.
The foreshocks eased some of the built up stress on 60 to 100 miles of fault, and the main shock released stress on about 155 miles, but about 155 miles of fault remain unchanged, the researchers report today (Aug. 13) in Nature.
“There can still be a big earthquake there,” said Furlong. “It did not release the total hazard, but it told us something about this large earthquake area. That an 8.8 rupture does not always happen.”
The researchers were able to do this analysis in near real time because of the availability of large computing power and previously laid groundwork.
The computing power allowed researchers to model the fault more accurately. In the past, subduction zones were modeled as if they were on a plane, but the plate that is subducting curves underneath the other plate creating a 3-dimensional fault line. The researchers used a model that accounted for this curving and so more accurately recreated the stresses on the real geology at the fault.
“One of the things the U.S. Geological Survey and we have been doing is characterizing the major tectonic settings,” said Furlong.
“So when an earthquake is imminent, we do not need a lot of time for the background.”
In essence, they are creating a library of information about earthquake faults and have completed the first level, a general set of information on areas such as Japan, South America and the Caribbean. Now they are creating the levels of north and south Japan or Chile, Peru and Ecuador.
Knowing where the old earthquake occurred, how large it was and how long ago it happened, the researchers could look at the foreshocks, see how much stress they relieved and anticipate, at least in a small way, what would happen.
“This is what we need to do in the future in near real time for decision makers,” said Furlong.
Other researchers working on this project were Gavin P. Hayes, former Penn State Ph.D. student now at U.S.G.S.; Matthew W. Herman, graduate student in geoscience, Penn State; William D. Barnhart, Harley M. Benz and Paul S. Earle, U.S.G.S; Sebástian Riquelme and Sergio Barrientos, Centro Sismológico Nacional, Universidad de Chile; Eric Bergman, Global Seismological Services; and Sergey Samsonov, Canada Centre for Mapping and Earth Observations, Natural Resources Canada.
The National Science Foundation and the U.S.G.S. supported this research.
PLANTS MAY USE LANGUAGE TO COMMUNICATE WITH EACH OTHER, VIRGINIA TECH RESEARCHER FINDS
From the FMS Global News Desk of Jeanne Hambleton Source Virginia Tech News – National Science Foundation
BLACKSBURG, Va., Aug. 15, 2014 – A Virginia Tech scientist has discovered a potentially new form of plant communication, one that allows them to share an extraordinary amount of genetic information with one another.
The finding by Jim Westwood, a professor of plant pathology, physiology, and weed science in the College of Agriculture and Life Sciences, throws open the door to a new arena of science that explores how plants communicate with each other on a molecular level. It also gives scientists new insight into ways to fight parasitic weeds that wreak havoc on food crops in some of the poorest parts of the world.
His findings were published on Aug. 15 in the journal Science.
“The discovery of this novel form of inter-organism communication shows that this is happening a lot more than any one has previously realized,” said Westwood, who is an affiliated researcher with the Fralin Life Science Institute.
“Now that we have found that they are sharing all this information, the next question is, ‘What exactly are they telling each other?’.”
Westwood examined the relationship between a parasitic plant, dodder, and two host plants, Arabidopsis and tomatoes. In order to suck the moisture and nutrients out the host plants, dodder uses an appendage called a haustorium to penetrate the plant. Westwood previously broke new ground when he found that during this parasitic interaction, there is a transport of RNA between the two species. RNA translates information passed down from DNA, which is an organism’s blueprint.
His new work expands this scope of this exchange and examines the mRNA, or messenger RNA, which sends messages within cells telling them which actions to take, such as which proteins to code. It was thought that mRNA was very fragile and short-lived, so transferring it between species was unimaginable.
The Parasitic Plant Time lapse video was made by Virginia Tech, to see this parasitic plant in action, log on to http://vimeo.com/102858531
But Westwood found that during this parasitic relationship, thousands upon thousands of mRNA molecules were being exchanged between both plants, creating this open dialogue between the species that allows them to freely communicate.
Through this exchange, the parasitic plants may be dictating what the host plant should do, such as lowering its defenses so that the parasitic plant can more easily attack it. Westwood’s next project is aimed at finding out exactly what the mRNA are saying. His work is sponsored by the National Science Foundation.
Using this new found information, scientists can now examine if other organisms such a bacteria and fungi also exchange information in a similar fashion. His finding could also help solve issues of food scarcity.
“Parasitic plants such as witchweed and broomrape are serious problems for legumes and other crops that help feed some of the poorest regions in Africa and elsewhere,” said Julie Scholes, a professor at the University of Sheffield, U.K., who is familiar with Westwood’s work but was not part of this project.
“In addition to shedding new light on host-parasite communication, Westwood’s findings have exciting implications for the design of novel control strategies based on disrupting the mRNA information that the parasite uses to reprogram the host.”
Westwood said that while his finding is fascinating, how this is applied will be equally as interesting.
“The beauty of this discovery is that this mRNA could be the Achilles heel for parasites,” Westwood said. “This is all really exciting because there are so many potential implications surrounding this new information.”
Nationally ranked among the top research institutions of its kind, Virginia Tech’s College of Agriculture and Life Sciences focuses on the science and business of living systems through learning, discovery, and engagement. The college’s comprehensive curriculum gives more than 3,100 students in a dozen academic departments a balanced education that ranges from food and fiber production to economics to human health. Students learn from the world’s leading agricultural scientists, who bring the latest science and technology into the classroom.
In the UK we suffer from Bindweed, Couch grass, Ground elder, Horsetail, and possibly the worst, Japanese Knotweed. See the Royal Horticultural Society’s Gardening video for weed control. https://www.rhs.org.uk/videos/advice/weed-control.
SCIENTIST UNCOVERS RED PLANET’S CLIMATE HISTORY IN UNIQUE METEORITE
From the FMS Global News Desk of Jeanne Hambleton Released: 27-Aug-2014 Source: Florida State University
Newswise — TALLAHASSEE, Fla. — Was Mars — now a cold, dry place — once a warm, wet planet that sustained life? And if so, how long has it been cold and dry?
Research underway at the National High Magnetic Field Laboratory may one day answer those questions — and perhaps even help pave the way for future colonization of the Red Planet. By analyzing the chemical clues locked inside an ancient Martian meteorite known as Black Beauty, Florida State University Professor Munir Humayun and an international research team are revealing the story of Mars’ ancient, and sometimes startling, climate history.
The team’s most recent finding of a dramatic climate change appeared in Nature Geoscience, in the paper “Record of the ancient Martian hydrosphere and atmosphere preserved in zircon from a Martian meteorite.”
The scientists found evidence for the climate shift in minerals called zircons embedded inside the dark, glossy meteorite. Zircons, which are also abundant in the Earth’s crust, form when lava cools. Among their intriguing properties, Humayun says, is that “they stick around forever.”
“When you find a zircon, it’s like finding a watch,” Humayun said. “A zircon begins keeping track of time from the moment it’s born.”
Last year, Humayun’s team correctly determined that the zircons in its Black Beauty sample were an astonishing 4.4 billion years old. That means, Humayun says, it formed during the Red Planet’s infancy and during a time when the planet might have been able to sustain life.
“First we learned that, about 4.5 billion years ago, water was more abundant on Mars, and now we have learned that something dramatically changed that,” said Humayun, a professor of geochemistry.
“Now we can conclude that the conditions that we see today on Mars, this dry Martian desert, must have persisted for at least the past 1.7 billion years. We know now that Mars has been dry for a very long time.”
The secret to Mars’ climate lies in the fact that zircons (ZrSiO4) contain oxygen, an element with three isotopes. Isotopes are atoms of the same element that have the same number of protons but a different number of neutrons — sort of like members of a family who share the same last name but have different first names.
On Mars, oxygen is distributed in the atmosphere (as carbon dioxide, molecular oxygen and ozone), in the hydrosphere (as water) and in rocks. In the thin, dry Martian atmosphere, the sun’s ultraviolet light causes unique shifts in the proportions in which the three isotopes of oxygen occur in the different atmospheric gases.
So when water vapor that has cycled through the Martian atmosphere condenses into the Martian soil, it can interact with and exchange oxygen isotopes with zircons in the soil, effectively writing a climate record into the rocks. A warm, wet Mars requires a dense atmosphere that filters out the ultraviolet light making the unique isotope shifts disappear.
In order to measure the proportions of the oxygen isotopes in the zircons, the team, led by scientist Alexander Nemchin, used a device called an ion microprobe. The instrument is in the NordSIMS facility at the Swedish Museum of Natural History, directed by team member Martin Whitehouse.
Because of these precise measurements, said Humayun, “we now have an isotopic record of how the atmosphere changed, with dates on it.”
The Black Beauty meteorite Humayun’s team is studying was discovered in the Sahara Desert in 2011. It is also known as NWA 7533, which stands for Northwest Africa, the location where it was found.
In all, more than five pieces of Black Beauty were found by Bedouin tribesmen, who make a living scouring the Sahara for meteorites and fossils that they can sell. The zircons analyzed by Humayun’s team were from Black Beauty samples kept in Paris.
Back tomorrow. Jeanne