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Scientists remove one of the final barriers to making lifelike robots

(L) The electrically actuated muscle with thin resistive wire in a rest position; (R) The muscle is expanded using only a low voltage (8V). (credit: Aslan Miriyev/Columbia Engineering)

Researchers at the Columbia Engineering Creative Machines lab have developed a 3D-printable, synthetic soft muscle that can mimic natural biological systems, lifting 1000 times its own weight. The artificial muscle is three times stronger than natural muscle and can push, pull, bend, twist, and lift weight — no external devices required.

Existing soft-actuator technologies are typically based on bulky pneumatic or hydraulic inflation of elastomer skins that expand when air or liquid is supplied to them, which require external compressors and pressure-regulating equipment.

“We’ve been making great strides toward making robot minds, but robot bodies are still primitive,” said Hod Lipson, PhD, a professor of mechanical engineering. “This is a big piece of the puzzle and, like biology, the new actuator can be shaped and reshaped a thousand ways. We’ve overcome one of the final barriers to making lifelike robots.”

The research findings are described in an open-access study published Tuesday Sept. 19, 2017 by Nature Communications.

Replicating natural motion

Inspired by living organisms, soft-material robotics hold promise for areas where robots need to contact and interact with humans, such as manufacturing and healthcare. Unlike rigid robots, soft robots can replicate natural motion — grasping and manipulation — to provide medical and other types of assistance, perform delicate tasks, or pick up soft objects.

Structure and principle of operation of the soft composite material (stereoscope image scale bar is 1 mm). Upon heating the composite to a temperature of 78.4 °C, ethanol boils and the local pressure inside the micro-bubbles grows, forcing the elastic silicone elastomer matrix to comply by expansion in order to reduce the pressure. (credit: Aslan Miriyev et al./Nature Communications)

To achieve an actuator with high stress and high strain coupled with low density, the researchers used a silicone rubber matrix with ethanol (alcohol) distributed throughout in micro-bubbles. This design combines the elastic properties and extreme volume change attributes of other material systems while also being easy to fabricate, low cost, and made of environmentally safe materials.*

The researchers next plan to use conductive (heatable) materials to replace the embedded wire, accelerate the muscle’s response time, and increase its shelf life. Long-term, they plan to involve artificial intelligence to learn to control the muscle — perhaps a final milestone towards replicating natural human motion.

* After being 3D-printed into the desired shape, the artificial muscle was electrically actuated using a thin resistive wire and low-power (8V). It was tested in a variety of robotic applications, where it showed significant expansion-contraction ability and was capable of expansion up to 900% when electrically heated to 80°C. The new material has a strain density (the amount of deformation in the direction of an applied force without damage) that is 15 times larger than natural muscle.


Columbia Engineering | Soft Materials for Soft Actuators

Roboticists show off their new advances in “soft robots” (credit: Reuters TV)

Abstract of Soft material for soft actuators

Inspired by natural muscle, a key challenge in soft robotics is to develop self-contained electrically driven soft actuators with high strain density. Various characteristics of existing technologies, such as the high voltages required to trigger electroactive polymers ( > 1KV), low strain ( < 10%) of shape memory alloys and the need for external compressors and pressure-regulating components for hydraulic or pneumatic fluidicelastomer actuators, limit their practicality for untethered applications. Here we show a single self-contained soft robust composite material that combines the elastic properties of a polymeric matrix and the extreme volume change accompanying liquid–vapor transition. The material combines a high strain (up to 900%) and correspondingly high stress (up to 1.3 MPa) with low density (0.84 g cm−3). Along with its extremely low cost (about 3 cent per gram), simplicity of fabrication and environment-friendliness, these properties could enable new kinds of electrically driven entirely soft robots.

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New system allows near-zero-power sensors to communicate data over long distances

This low-cost, flexible epidermal medical-data patch prototype successfully transmitted information at up to 37500 bits per second across a 3,300-square-feet atrium. (credit: Dennis Wise/University of Washington)

University of Washington (UW) researchers have developed a low-cost, long-range data-communication system that could make it possible for medical sensors or billions of low-cost “internet of things” objects to connect via radio signals at long distances (up to 2.8 kilometers) and with 1000 times lower required power (9.25 microwatts in an experiment) compared to existing technologies.

“People have been talking about embedding connectivity into everyday objects … for years, but the problem is the cost and power consumption to achieve this,” said Vamsi Talla, chief technology officer of Jeeva Wireless, which plans to market the system within six months. “This is the first wireless system that can inject connectivity into any device with very minimal cost.”

The new system uses “backscatter,” which uses energy from ambient transmissions (from WiFi, for example) to power a passive sensor that encodes and scatter-reflects the signal. (This article explains how ambient backscatter, developed by UW, works.) Backscatter systems, used with RFID chips, are very low cost, but are limited in distance.

So the researchers combined backscatter with a “chirp spread spectrum” technique, used in LoRa (long-range) wireless data-communication systems.

This tiny off-the-shelf spread-spectrum receiver enables extremely-low-power cheap sensors to communicate over long distances. (credit: Dennis Wise/University of Washington)

This new system has three components: a power source (which can be WiFi or other ambient transmission sources, or cheap flexible printed batteries, with an expected bulk cost of 10 to 20 cents each) for a radio signal; cheap sensors (less than 10 cents at scale) that modulate (encode) information (contained in scattered reflections of the signal), and an inexpensive, off-the-shelf spread-spectrum receiver, located as far away as 2.8 kilometers, that decodes the sensor information.

Applications could include, for example, medical monitoring devices that wirelessly transmit information about a heart patient’s condition to doctors; sensor arrays that monitor pollution, noise, or traffic in “smart” cities; and farmers looking to measure soil temperature or moisture, who could affordably blanket an entire field to determine how to efficiently plant seeds or water.

The research team built a contact lens prototype and a flexible epidermal patch that attaches to human skin, which successfully used long-range backscatter to transmit information across a 3300-square-foot building.

The research, which was partially funded by the National Science Foundation, is detailed in an open-access paper presented Sept. 13, 2017 at UbiComp 2017. More information: longrange@cs.washington.edu.


UW (University of Washington) | UW team shatters long-range communication barrier for devices that consume almost no power

Abstract of LoRa Backscatter: Enabling The Vision of Ubiquitous Connectivity

The vision of embedding connectivity into billions of everyday objects runs into the reality of existing communication technologies — there is no existing wireless technology that can provide reliable and long-range communication at tens of microwatts of power as well as cost less than a dime. While backscatter is low-power and low-cost, it is known to be limited to short ranges. This paper overturns this conventional wisdom about backscatter and presents the first wide-area backscatter system. Our design can successfully backscatter from any location between an RF source and receiver, separated by 475 m, while being compatible with commodity LoRa hardware. Further, when our backscatter device is co-located with the RF source, the receiver can be as far as 2.8 km away. We deploy our system in a 4,800 ft2 (446 m2) house spread across three floors, a 13,024 ft2 (1210 m2) office area covering 41 rooms, as well as a one-acre (4046 m2) vegetable farm and show that we can achieve reliable coverage, using only a single RF source and receiver. We also build a contact lens prototype as well as a flexible epidermal patch device attached to the human skin. We show that these devices can reliably backscatter data across a 3,328 ft2 (309 m2) room. Finally, we present a design sketch of a LoRa backscatter IC that shows that it costs less than a dime at scale and consumes only 9.25 &mgr;W of power, which is more than 1000x lower power than LoRa radio chipsets.

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Walking DNA nanorobot could deliver a drug to a precise location in your body

DNA nanorobot cargo carrier (artist’s impression) (credit: Ella Maru Studio)

Caltech scientists have developed a “cargo sorting” DNA nanorobot programmed to autonomously “walk” around a surface, pick up certain molecules, and drop them off in designated locations.

The research is described in a paper in the Friday, September 15, 2017 issue of Science.

The major advance in this study is “their methodology for designing simple DNA devices that work in parallel to solve nontrivial tasks,” notes Duke University computer scientist John H. Reif in an article in the same issue of Science.

Such tasks could include synthesizing a drug in a molecular factory or delivering a drug only when a specific signal is present in bloodstreams, say the researchers. “So far, the development of DNA robots has been limited to simple functions,” the researchers note.

Walking nanobots that work in parallel

Conceptual illustration of two DNA nanorobots collectively performing a cargo-sorting task on a DNA origami surface: transporting fluorescent molecules with different colors from initially random locations to ordered destinations. (credit: Demin Liu)

The DNA nanorobot, intended as a proof of concept, has a “leg” with two “feet” for walking, and an “arm” and “hand” for picking up cargo. It also has a segment that can recognize a specific drop-off point and signal to the hand to release its cargo. Each of these building blocks are made of just a few nucleotides (molecules that form DNA) within a single strand of DNA.*

As the robot encounters cargo molecules tethered to pegs, it grabs them with its “hand” components and carries them around (with a 6-nm step size) until it detects the signal of the drop-off point.

Multiple DNA nanorobots independently execute three operations in parallel: [1] cargo pickup, [2] random movement to adjacent stepping stones, and [3] cargo drop-off at ordered locations. (credit: C. Bickel/Science)

In experiments, the nanorobots successfully sorted six randomly scattered molecules into their correct places in 24 hours. The process is slow, but adding more robots to the surface shortened the time it took to complete the task. The very simple robot design utilizes very little chemical energy, according to the researchers.**

“The same system design can be generalized to work with dozens of types of cargos at any arbitrary initial location on the surface,” says lead author Anupama Thubagere. “One could also have multiple robots performing diverse sorting tasks in parallel,” [programmed] like macroscopic robots.”

Future applications

“We don’t develop DNA robots for any specific applications. Our lab focuses on discovering the engineering principles that enable the development of general-purpose DNA robots,” explains Lulu Qian, assistant professor of bioengineering.

“However, it is my hope that other researchers could use these principles for exciting applications, such as synthesizing a therapeutic chemical from its constituent parts in an artificial molecular factory, or sorting molecular components in trash for recycling. Just like electromechanical robots are sent off to faraway places, like Mars, we would like to send molecular robots to minuscule places where humans can’t go, such as the bloodstream.”

Funding was provided by Caltech Summer Undergraduate Research Fellowships, the National Science Foundation, and the Burroughs Wellcome Fund.

* The key to designing DNA machines is the fact that DNA has unique chemical and physical properties that are known and programmable. A single strand of DNA is made up of four different molecules called nucleotides—abbreviated A, G, C, and T—and arranged in a string called a sequence. These nucleotides bond in specific pairs: A with T, and G with C. When a single strand encounters a “reverse complementary strand” — for example, CGATT meets AATCG —the two strands zip together in the classic double-helix shape.

** Using these chemical and physical principles, researchers can also design “playgrounds,” such as molecular pegboards, to test them on, according to the researchers. In the current work, the DNA robot moves around on a 58-nanometer-by-58-nanometer pegboard on which the pegs are made of single strands of DNA complementary to the robot’s leg and foot. The robot binds to a peg with its leg and one of its feet — the other foot floats freely. When random molecular fluctuations cause this free foot to encounter a nearby peg, it pulls the robot to the new peg and its other foot is freed. This process continues with the robot moving in a random direction at each step.

Abstract of A cargo-sorting DNA robot

Two critical challenges in the design and synthesis of molecular robots are modularity and
algorithm simplicity.We demonstrate three modular building blocks for a DNA robot that
performs cargo sorting at themolecular level. A simple algorithm encoding recognition between
cargos and their destinations allows for a simple robot design: a single-stranded DNA with
one leg and two foot domains for walking, and one arm and one hand domain for picking up and
dropping off cargos.The robot explores a two-dimensional testing ground on the surface of
DNA origami, picks up multiple cargos of two types that are initially at unordered locations, and
delivers them to specified destinations until all molecules are sorted into two distinct piles.
The robot is designed to perform a random walk without any energy supply. Exploiting this
feature, a single robot can repeatedly sort multiple cargos. Localization on DNA origami allows
for distinct cargo-sorting tasks to take place simultaneously in one test tube or for multiple
robots to collectively perform the same task.

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Miniature MRI simulator chip could help diagnose and treat diseases in the body at sub-millimeter precision

Illustration of an ATOMS microchip localized within the gastrointestinal tract (not to scale; a prototype measures just 0.7 cubic millimeters). The microchip contains a magnetic field sensor, integrated antennas, a wireless powering device, and a circuit that adjusts its radio frequency signal based on the magnetic field strength and wirelessly relays the chip’s precise location. (credit: Ella Marushchenko/Caltech)

Caltech researchers have developed a “Fantastic Voyage” style prototype microchip that could one day be used in “smart pills” to diagnose and treat diseases when inserted into the human body.

Called ATOMS (addressable transmitters operated as magnetic spins), the microchips could one day monitor a patient’s gastrointestinal tract, blood, or brain, measuring factors that indicate a patient’s health — such as pH, temperature, pressure, and sugar concentrations — with sub-millimeter localization and relay that information to doctors. Or the devices could even be instructed to release drugs at precise locations.

An open access paper describing the new device appears in the September issue of the journal Nature Biomedical Engineering. The lead author is Manuel Monge, who now works at Elon Musk’s new Neuralink company.

The ATOMS microchips, proven to work in tests with mice, mimic the way nuclear spins in atoms in the body resonate to magnetic fields in a magnetic resonance imaging (MRI) machine and can be precisely identified and localized within the body. Similarly, the ATOMS devices resonate at different frequencies depending on where they are in a magnetic field. (credit: Manuel Monge et al./ Nature Biomedical Engineering)

Abstract of Localization of Microscale Devices In Vivo using Addressable Transmitters Operated as Magnetic Spins

The function of miniature wireless medical devices, such as capsule endoscopes, biosensors and drug-delivery systems, depends critically on their location inside the body. However, existing electromagnetic, acoustic and imaging-based methods for localizing and communicating with such devices suffer from limitations arising from physical tissue properties or from the performance of the imaging modality. Here, we embody the principles of nuclear magnetic resonance in a silicon integrated-circuit approach for microscale device localization. Analogous to the behaviour of nuclear spins, the engineered miniaturized radio frequency transmitters encode their location in space by shifting their output frequency in proportion to the local magnetic field; applied field gradients thus allow each device to be located precisely from its signal’s frequency. The devices are integrated in circuits smaller than 0.7 mm3 and manufactured through a standard complementary-metal-oxide-semiconductor process, and are capable of sub-millimetre localization in vitro and in vivo. The technology is inherently robust to tissue properties, scalable to multiple devices, and suitable for the development of microscale devices to monitor and treat disease.

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‘Fog computing’ could improve communications during natural disasters

Hurricane Irma at peak intensity near the U.S. Virgin Islands on September 6, 2017 (credit: NOAA)

Researchers at the Georgia Institute of Technology have developed a system that uses edge computing (also known as fog computing) to deal with the loss of internet access in natural disasters such as hurricanes, tornados, and floods.

The idea is to create an ad hoc decentralized network that uses computing power built into mobile phones, routers, and other hardware to provide actionable data to emergency managers and first responders.

In a flooded area, for example, search and rescue personnel could continuously ping enabled phones, surveillance cameras, and “internet of things” devices in an area to determine their exact locations. That data could then be used to create density maps of people to prioritize and guide emergency response teams.

Situational awareness for first responders

“We believe fog computing can become a potent enabler of decentralized, local social sensing services that can operate when internet connectivity is constrained,” said Kishore Ramachandran, PhD, computer science professor at Georgia Tech and senior author of a paper presented in April this year at the 2nd International Workshop on Social Sensing*.

“This capability will provide first responders and others with the level of situational awareness they need to make effective decisions in emergency situations.”

The team has proposed a generic software architecture for social sensing applications that is capable of exploiting the fog-enabled devices. The design has three components: a central management function that resides in the cloud, a data processing element placed in the fog infrastructure, and a sensing component on the user’s device.

Beyond emergency response during natural disasters, the team believes its proposed fog architecture can also benefit communities with limited or no internet access — for public transportation management, job recruitment, and housing, for example.

To monitor far-flung devices in areas with no internet access, a bus or other vehicle could be outfitted with fog-enabled sensing capabilities, the team suggests. As it travels in remote areas, it would collect data from sensing devices. Once in range of internet connectivity, the “data mule” bus would upload that information to centralized cloud-based platforms.

* “Social sensing has emerged as a new paradigm for collecting sensory measurements by means of “crowd-sourcing” sensory data collection tasks to a human population. Humans can act as sensor carriers (e.g., carrying GPS devices that share location data), sensor operators (e.g., taking pictures with smart phones), or as sensors themselves (e.g., sharing their observations on Twitter). The proliferation of sensors in the possession of the average individual, together with the popularity of social networks that allow massive information dissemination, heralds an era of social sensing that brings about new research challenges and opportunities in this emerging field.” — SocialSens2017

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These fast, low-cost medical technologies will replace ultrasound and X-rays for specific uses

Smartphone instant heart diagnosis (credit: Caltech)

A radical software invention by three Caltech engineers promises to allow your smartphone camera* to provide detailed information about a critical measure of your heart’s health: the “left ventricular ejection fraction” (LVEF) — the amount of blood in the heart that is pumped out to the blood system with each beat. This figure is used by physicians as a base for diagnostic and therapeutic decisions.

You’ll simply hold your phone up to your neck for a minute or two.

In an experiment, the technique was found to be as accurate as a 45-minute echocardiography scan, which currently requires a trained technician operating an expensive ultrasound machine.

The smartphone technique measures how much the carotid artery displaces the skin of the neck as blood pumps through it. In a normal heart, the LVEF measure ranges from 50 to 70 percent. When the heart is weaker, less of the total amount of blood in the heart is pumped out with each beat, and the LVEF value is lower.

Carotid arterial waveform captured using an unmodified iPhone 5S camera by placing the iPhone camera over the carotid pulse (credit: Niema M. Pahlevan et al./Critical Card Medicine)

To test the app, clinical trials were conducted with 72 volunteers between the ages of 20 and 92 at an outpatient magnetic resonance imaging (MRI) facility. MRI is the gold standard in measuring LVEF but is seldom used clinically due to its high cost and limited availability. The measurements made by smartphone had a margin of error of ±19.1 percent compared with those done in an MRI. By way of comparison, the margin of error for echocardiography is around ±20.0 percent.

“This has the potential to revolutionize how doctors and patients can screen for and monitor heart disease, both in the U.S. and the developing world,” says Caltech’s Mory Gharib, the Hans W. Liepmann Professor of Aeronautics and Bioinspired Engineering and senior author of a paper on the study in the July issue of the Journal of Critical Care Medicine.

The researchers have founded a start-up named Avicena, LLC that has licensed this technology and will market the app. They also plan to use this approach to diagnose heart-valve diseases, like aortic stenosis and coronary artery blockage.

* For the study, the team used an iPhone 5, but they say any smartphone with a camera will work.

Seeing through the body

University of Edinburgh and Heriot-Watt University researchers have used a near-infrared camera to see through the chest to track the location of a fiber-optic endomicroscope (a long flexible tube with a light on the end) — replacing X-rays.

A “time-of-flight” camera detects light emitted from an endoscope in sheep lungs. Left: light emitted from the tip of the endoscope, revealing its precise location in the lungs. Right: an image using a conventional camera, with light scattered through the structures of the lung. (credit: Proteus)

Near-infrared light can readily pass through the body, but much of it scatters or bounces off tissues and organs rather than traveling straight through — making it nearly impossible to get a clear picture of where an object is in the body. So this camera uses a “time-of-flight” system: It calculates the distance to the endomicroscope light based on the time it takes individual photons to arrive directly (ignoring scattered photons, which take longer). That’s similar to how this camera can see an object around a corner.

The technology is so sensitive it can detect the miniscule amount of light that passes through 20 centimeters (about 8 inches) of the body’s tissue.

The research is described in an open-access paper in the journal Biomedical Optics Express.

Abstract of Noninvasive iPhone Measurement of Left Ventricular Ejection Fraction Using Intrinsic Frequency Methodology

Objective: The study is based on previously reported mathematical analysis of arterial waveform that extracts hidden oscillations in the waveform that we called intrinsic frequencies. The goal of this clinical study was to compare the accuracy of left ventricular ejection fraction derived from intrinsic frequencies noninvasively versus left ventricular ejection fraction obtained with cardiac MRI, the most accurate method for left ventricular ejection fraction measurement.

Design: After informed consent, in one visit, subjects underwent cardiac MRI examination and noninvasive capture of a carotid waveform using an iPhone camera (The waveform is captured using a custom app that constructs the waveform from skin displacement images during the cardiac cycle.). The waveform was analyzed using intrinsic frequency algorithm.

Setting: Outpatient MRI facility.

Subjects: Adults able to undergo MRI were referred by local physicians or self-referred in response to local advertisement and included patients with heart failure with reduced ejection fraction diagnosed by a cardiologist.

Interventions: Standard cardiac MRI sequences were used, with periodic breath holding for image stabilization. To minimize motion artifact, the iPhone camera was held in a cradle over the carotid artery during iPhone measurements.

Measurements and Main Results: Regardless of neck morphology, carotid waveforms were captured in all subjects, within seconds to minutes. Seventy-two patients were studied, ranging in age from 20 to 92 years old. The main endpoint of analysis was left ventricular ejection fraction; overall, the correlation between ejection fraction–iPhone and ejection fraction–MRI was 0.74 (r = 0.74; p < 0.0001; ejection fraction–MRI = 0.93 × [ejection fraction–iPhone] + 1.9).

Conclusions: Analysis of carotid waveforms using intrinsic frequency methods can be used to document left ventricular ejection fraction with accuracy comparable with that of MRI. The measurements require no training to perform or interpret, no calibration, and can be repeated at the bedside to generate almost continuous analysis of left ventricular ejection fraction without arterial cannulation.

Abstract of Ballistic and snake photon imaging for locating optical endomicroscopy fibres

We demonstrate determination of the location of the distal-end of a fibre-optic device deep in tissue through the imaging of ballistic and snake photons using a time resolved single-photon detector array. The fibre was imaged with centimetre resolution, within clinically relevant settings and models. This technique can overcome the limitations imposed by tissue scattering in optically determining the in vivo location of fibre-optic medical instruments.

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A cooling system that works without electricity

Fluid-cooling panels being tested on the roof of a Stanford University building (credit: Aaswath Raman)

Stanford University scientists have developed a high-tech mirror-like optical surface that uses “radiative sky cooling” to dramatically lower the energy required for air conditioning and refrigeration.

The system cools water (flowing through pipes connected to an air-conditioning system) without requiring electricity by radiating excess heat from water into cold space. Panels covered in specialized optical surfaces reflect about 97 percent of the sunlight while simultaneously emitting the surface’s thermal energy through the atmosphere.

In a test on the roof of a Stanford University building, the panels were able to reduce the water temperature 3 to 5 degrees Celsius below ambient air temperature, allowing for a connected air conditioning system to lower its electricity use.

Modeling cooling system-level energy savings. The fluid cooling panels (top) reduce electricity consumption in cooling systems, such as an air-cooled condenser-based system used in the Las Vegas study. (credit: Eli A. Goldstein, Aaswath P. Raman and Shanhui Fan/Nature Energy)

The researchers modeled a cooling system of a two-story commercial building in a hot dry climate (Las Vegas) with this panel-cooled system installed. They found it would save 14.3 megawatt-hours of electricity in the summer months — a 21 percent reduction in the electricity used to cool the building.

The system would also reduce the significant water loss in cooling systems using evaporative cooling.

As the researchers, led by Shanhui Fan, professor of electrical engineering, write in a paper published in Nature Energy Sept. 4, “cooling systems consume 15% of electricity generated globally and account for 10% of global greenhouse gas emissions.”

They note that “with demand for cooling expected to grow tenfold by 2050, improving the efficiency of cooling systems is a critical part of the twenty-first-century energy challenge.”

The researchers have founded the company SkyCool Systems, which is working on further testing and commercializing this technology. They are focused on making their panels integrate easily with standard air conditioning and refrigeration systems, and are especially interested in cooling data centers.

This work was funded by the Advanced Research Projects Agency – Energy (ARPA-E) of the Department of Energy.

Abstract of Sub-ambient non-evaporative fluid cooling with the sky

Cooling systems consume 15% of electricity generated globally and account for 10% of global greenhouse gas emissions. With demand for cooling expected to grow tenfold by 2050, improving the efficiency of cooling systems is a critical part of the twenty-first-century energy challenge. Building upon recent demonstrations of daytime radiative sky cooling, here we demonstrate fluid cooling panels that harness radiative sky cooling to cool fluids below the air temperature with zero evaporative losses, and use almost no electricity. Over three days of testing, we show that the panels cool water up to 5 ∘C below the ambient air temperature at water flow rates of 0.2 l min−1 m−2, corresponding to an effective heat rejection flux of up to 70 W m−2. We further show through modelling that, when integrated on the condenser side of the cooling system of a two-storey office building in a hot dry climate (Las Vegas, USA), electricity consumption for cooling during the summer could be reduced by 21% (14.3 MWh).

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Leading AI country will be ‘ruler of the world,’ says Putin

DoD autonomous drone swarms concept (credit: U.S. Dept. of Defense)

Russian President Vladimir Putin warned Friday (Sept. 1, 2017) that the country that becomes the leader in developing artificial intelligence will be “the ruler of the world,” reports the Associated Press.

AI development “raises colossal opportunities and threats that are difficult to predict now,” Putin said in a lecture to students, warning that “it would be strongly undesirable if someone wins a monopolist position.”

Future wars will be fought by autonomous drones, Putin suggested, and “when one party’s drones are destroyed by drones of another, it will have no other choice but to surrender.”

U.N. urged to address lethal autonomous weapons

AI experts worldwide are also concerned. On August 20, 116 founders of robotics and artificial intelligence companies from 26 countries, including Elon Musk* and Google DeepMind’s Mustafa Suleyman, signed an open letter asking the United Nations to “urgently address the challenge of lethal autonomous weapons (often called ‘killer robots’) and ban their use internationally.”

“Lethal autonomous weapons threaten to become the third revolution in warfare,” the letter states. “Once developed, they will permit armed conflict to be fought at a scale greater than ever, and at timescales faster than humans can comprehend. These can be weapons of terror, weapons that despots and terrorists use against innocent populations, and weapons hacked to behave in undesirable ways. We do not have long to act. Once this Pandora’s box is opened, it will be hard to close.”

Unfortunately, the box may have already been opened. Three examples:

Russia. In 2014, Dmitry Andreyev of the Russian Strategic Missile Forces announced that mobile robots would be standing guard over five ballistic missile installations, New Scientist reported. Armed with a heavy machine gun, this “mobile robotic complex … can detect and destroy targets, without human involvement.”

Uran-9 unmanned combat ground vehicle (credit: Vitaly V. Kuzmin/CC)

In 2016, Russian military equipment manufacturer JSC 766 UPTK announced what appears to be the commercial version: the Uran-9 multipurpose unmanned ground combat vehicle. “In autonomous mode, the vehicle can automatically identify, detect, track and defend [against] enemy targets based on the pre-programmed path set by the operator,” the company said.

United States. In a 2016 report, the U.S. Department of Defense advocated self-organizing “autonomous unmanned” (UA) swarms of small drones that would assist frontline troops in real time by surveillance, jamming/spoofing enemy electronics, and autonomously firing against the enemy.

The authors warned that “autonomy — fueled by advances in artificial intelligence — has attained a ‘tipping point’ in value. Autonomous capabilities are increasingly ubiquitous and are readily available to allies and adversaries alike.” The report advised that the Department of Defense “must take immediate action to accelerate its exploitation of autonomy while also preparing to counter autonomy employed by adversaries.”**

South Korea. Designed initially for the DMZ, Super aEgis II, a robot-sentry machine gun designed by Dodaam Systems, can identify, track, and automatically destroy a human target 3 kilometers away, assuming that capability is turned on.

* “China, Russia, soon all countries w strong computer science. Competition for AI superiority at national level most likely cause of WW3 imo.” — Elon Musk tweet 2:33 AM – 4 Sep 2017

** While it doesn’t use AI, the U.S. Navy’s computer-controlled, radar-guided Phalanx gun system can automatically detect, track, evaluate, and fire at incoming missiles and aircraft that it judges to be a threat.

UPDATE Sept. 5, 2017: Added Musk tweet in footnote

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A single-molecule room-temperature transistor made from 14 atoms

Columbia researchers wired a single molecule consisting of 14 atoms connected to two gold electrodes to show that it performs as a transistor at room temperature. (credit: Bonnie Choi/Columbia University)

Columbia Engineering researchers have taken a key step toward atomically precise, reproducible transistors made from single molecules and operating at room temperature — a major goal in the field of molecular electronics.

The team created a two-terminal transistor with a diameter of about 0.5 nanometers and core consisting of just 14 atoms. The device can reliably switch from insulator to conductor when charge is added or removed, one electron at a time (known as “current blockade”).*

The research was published in the journal Nature Nanotechnology.

Controllable structure with atomic precision

“With these molecular clusters, we have complete control over their structure with atomic precision and can change the elemental composition and structure in a controllable manner to elicit certain electrical response,” says Latha Venkataraman, leader of the Columbia research team.

The researchers plan to design improved molecular cluster systems with better electrical performance (such as higher on/off current ratio and different accessible states) and increase the number of atoms in the cluster core, while maintaining the atomic precision and uniformity of the compound.

Other studies have created quantum dots to produce similar effects, but the dots are much larger and not uniform in size, and the results have not been reproducible. The ultimate size reduction would be single-atom transistors, but they require ultra-cold temperatures (minus 196 degrees Celsius in this case, for example).

The single molecule’s 14-atom core structure comprises cobalt (blue) and sulfur (yellow) atoms (left) and ethyl-4-(methylthio)phenyl phosphine atoms, used to wire the cluster into a junction (right). (credit: Bonnie Choi/Columbia University)

* The researchers used a scanning tunneling microscope technique that they pioneered to make junctions comprising a single cluster connected to the two gold electrodes, which enabled them to characterize its electrical response as they varied the applied bias voltage. The technique allows them to fabricate and measure thousands of junctions with reproducible transport characteristics. The team worked with small inorganic molecular clusters that were identical in shape and size, so they knew exactly — down to the atomic scale — what they were measuring. The team evaluated the performance of the diode by the on/off ratio — the ratio between the current flowing through the device when it is switched on and the residual current still present in its “off” state. At room temperature, they observed a high on/off ratio of about 600 in single-cluster junctions, higher than any other single-molecule devices measured to date.

Abstract of Room-temperature current blockade in atomically defined single-cluster junctions

Fabricating nanoscopic devices capable of manipulating and processing single units of charge is an essential step towards creating functional devices where quantum effects dominate transport characteristics. The archetypal single-electron transistor comprises a small conducting or semiconducting island separated from two metallic reservoirs by insulating barriers. By enabling the transfer of a well-defined number of charge carriers between the island and the reservoirs, such a device may enable discrete single-electron operations. Here, we describe a single-molecule junction comprising a redox-active, atomically precise cobalt chalcogenide cluster wired between two nanoscopic electrodes. We observe current blockade at room temperature in thousands of single-cluster junctions. Below a threshold voltage, charge transfer across the junction is suppressed. The device is turned on when the temporary occupation of the core states by a transiting carrier is energetically enabled, resulting in a sequential tunnelling process and an increase in current by a factor of ∼600. We perform in situ and ex situ cyclic voltammetry as well as density functional theory calculations to unveil a two-step process mediated by an orbital localized on the core of the cluster in which charge carriers reside before tunnelling to the collector reservoir. As the bias window of the junction is opened wide enough to include one of the cluster frontier orbitals, the current blockade is lifted and charge carriers can tunnel sequentially across the junction.

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Astronomers detect 15 high-frequency ‘fast radio bursts’ from distant galaxy

Green Bank Telescope in West Virginia (credit: Geremia/CC)

Using the Green Bank radio telescope, astronomers at Breakthrough Listen, a $100 million initiative to find signs of intelligent life in the universe, have detected 15 brief but powerful “fast radio bursts” (FRBs). These microwave radio pulses are from a mysterious source known as FRB 121102* in a dwarf galaxy about 3 billion light years from Earth, transmitting at record high frequencies (4 to 8 GHz), according to the researchers

This sequence of 14 of the 15 detected fast radio bursts illustrates their dispersed spectrum and extreme variability. The streaks across the colored energy plot are the bursts appearing at different times and different energies because of dispersion caused by 3 billion years of travel through intergalactic space. In the top frequency spectrum, the dispersion has been removed to show the 300 microsecond pulse spike. (credit: Berkeley SETI Research Center)

Andrew Siemion, director of the Berkeley SETI Research Center and of the Breakthrough Listen program, and his team alerted the astronomical community to the high-frequency activity via an Astronomer’s Telegram on Monday evening, Aug. 28.

A schematic illustration of CSIRO’s Parkes radio telescope in Australia receiving a fast radio burst signal in 2014 (credit: Swinburne Astronomy Productions)

First detected in 2007, fast radio bursts are brief, bright pulses of radio emission detected from distant but largely unknown sources.

Breakthrough Starshot’s plan to use powerful laser pulses to propel nano-spacecraft to Proxima Centauri (credit: Breakthrough Initiatives)

Possible explanations for the repeating bursts range from outbursts from magnetars (rotating neutron stars with extremely strong magnetic fields) to directed energy sources — powerful bursts used by extraterrestrial civilizations to power exploratory spacecraft, akin to Breakthrough Starshot’s plan to use powerful laser pulses to propel nano-spacecraft to Earth’s nearest star, Proxima Centauri.

* FRB 121102 was discovered Nov 2, 2014 (hence its name) with the Arecibo radio telescope, and in 2015 it was the first fast radio burst seen to repeat. More than 150 high-energy bursts have been observed so far. (The repetition ruled out the possibility that FRBs were caused by catastrophic events.)

FRB 121102: Detection at 4 – 8 GHz band with Breakthrough Listen backend at Green Bank

On Saturday, August 26 at 13:51:44 UTC we initiated observations of the well-known repeating fast radio burst FRB 121102 [Spitler et al., Nature, 531, 7593 202-205, 2016] using the Breakthrough Listen Digital Backend with the C-band receiver at the Green Bank Telescope. We recorded baseband voltage data across 5.4375 GHz of bandwidth, completely covering the C-band receiver’s nominal 4-8 GHz band [MacMahon et al. arXiv:1707.06024v2]. Observations were conducted over ten 30-minute scans, as detailed in Table 1. Immediately after observations, the baseband data were reduced to form high time resolution (300 us integration) Stokes-I products using a GPU-accelerated spectroscopy suite. These reduced products were searched for dispersed pulses consistent with the known dispersion measure of FRB 121102 (557 pc cm^-3); baseband voltage data were preserved. We detected 15 bursts above our detection threshold of 10 sigma in the first two 30-minute scans, denoted 11A-L and 12A-B in Table 2. In Table 2, we include the detection signal-to-noise ratio (SNR) of each burst, along with a very rough estimate of pulse energy density assuming a 12 Jy system equivalent flux density, 300 us pulse width, and uniform 3800 MHz bandwidth. We note the following phenomenological properties of the detected bursts: 1. Bursts show marked changes in spectral extent, with characteristic spectral structure in the 100 MHz – 1 GHz range. 2. Several bursts appear to peak in brightness at frequencies above 6 GHz.