Computers Math

When there is a gas leak in a large building or at an industrial site, human firefighters currently need to go in with gas sensing instruments. Finding the gas leak may take considerable time, while they are risking their lives. Researchers from TU Delft (the Netherlands), University of Barcelona, and Harvard University have now developed the first swarm of tiny — and hence very safe — drones that can autonomously detect and localize gas sources in cluttered indoor environments.
The main challenge the researchers needed to solve was to design the Artificial Intelligence for this complex task that would fit in the tight computational and memory constraints of the tiny drones. They solved this challenge by means of bio-inspired navigation and search strategies. The scientific article has now been made public on the ArXiv article server, and it will be presented at the IROS robotics conference later this year. The work forms an important step in the intelligence of small robots and will allow finding gas leaks more efficiently and without the risk of human lives in real-world environments.
Autonomous gas source localization
Autonomous gas source localization is a complex task. For one, artificial gas sensors are currently less capable than animal noses in detecting small amounts of gas and staying sensitive to quick changes in gas concentration. Moreover, the environment in which the gas spreads can be complex. Consequently, much of the research in this area has focused on single robots that search for a gas source in rather small, obstacle-free environments in which the source is easier to find.
Swarms of tiny drones
“We are convinced that swarms of tiny drones are a promising avenue for autonomous gas source localization,” says Guido de Croon, Full Professor at the Micro Air Vehicle laboratory of TU Delft. “The drones’ tiny size makes them very safe to any humans and property still in the building, while their flying capability will allow them to eventually search for the source in three dimensions. Moreover, their small size allows them to fly in narrow indoor areas. Finally, having a swarm of these drones allows them to localize a gas source quicker, while escaping local maxima of gas concentration in order to find the true source.”
However, these properties also make it very hard to instill the drones with the necessary artificial intelligence for autonomous gas source localization. The onboard sensing and processing is extremely limited, excluding the type of AI algorithms that make self-driving cars autonomous. Moreover, operating in a swarm brings its own challenges, since the drones need to be aware of each other for collision avoidance and collaboration. More

Sharing ideas in an online learning environment has a distinct advantage over sharing personal details in driving learner engagement in massive open online courses, more commonly known as MOOCs, says new research co-written by a University of Illinois Urbana-Champaign expert who studies the intersection of marketing and digital environments.
Online learning engagement can be increased by nearly one-third by simply prompting students to share course ideas in a discussion forum rather than having them share information about their identity or personal motivations for enrolling, said Unnati Narang, a professor of business administration at the Gies College of Business.
With less than 10% of online learners completing courses, and less than 5% participating in course discussions, there’s a stark need for online learning platforms to identify and employ strategies that can enhance student engagement, Narang said.
“Engagement levels have tended to be really low in online classrooms simply because students may not ever get the chance to get to know each other in the way they do in an in-person, face-to-face classroom,” she said. “A lot of those elements are, quite obviously, lacking in the online learning environment.”
Initially, online platforms placed a lot of emphasis on having discussion forums to engage students. But over time, those efforts tended to fizzle out, Narang said.
“Even if a student is posting something, it may never be read by a classmate or by the instructor, which can really demotivate students who are trying to engage in the material,” she said.
To determine how to increase learner engagement, Narang and her co-authors analyzed more than 12,000 discussion forum postings during an 18-month period and conducted a field experiment involving more than 2,000 learners in a popular online course offered by a large U.S. university.
“We randomly nudged students to either share something personal about themselves or ideas related to the course,” she said. “We thought we were going to see an increase in engagement thanks to the social aspects of identity sharing because there’s so much emphasis on it in face-to-face classes for icebreakers and social introductions.”
The results indicated that asking learners to share ideas related to the course had a stronger effect on their video consumption and assessment completion, according to the paper.
“We found that the idea of sharing knowledge outperforms identity sharing as well as the control condition of not sharing anything,” Narang said. “Across diverse metrics of learner engagement and performance, we found that what learners share plays a big role in enhancing the online learning environment, and they tended to perform 30% better in terms of how many videos they consumed, how many assessments they completed and how they scored on assessments. So there’s a distinct advantage to idea sharing in online pedagogy.”
For educators, the implications of what the researchers dubbed the “idea advantage” in an era of increased online learning due to the COVID-19 pandemic suggests that identity sharing tends to be superficial and brief, so it’s better to push students to engage more on the course content and their ideas about what they’re studying, Narang said.
“Just very basic getting-to-know-you introductions that instructors make in a physical classroom — who are you, where you’re from, etc. — doesn’t really translate into the online learning environment,” she said. “There’s just too much anonymity to successfully do that when you’re in a virtual classroom. The idea posts, on the other hand, tend to be much more elaborate and well-articulated. Students put more time and effort into crafting their answers. On average, an idea-sharing post was 66 words long. But an identity-sharing post tended to be roughly half as long. Students were clearly more invested in ideas than trying to make friends in the online learning environment, thus why the idea advantage is so strong.” More

Many of us swing through gates every day — points of entry and exit to a space like a garden, park or subway. Electronics have gates too. These control the flow of information from one place to another by means of an electrical signal. Unlike a garden gate, these gates require control of their opening and closing many times faster than the blink of an eye.
Scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory and the University of Chicago’s Pritzker School of Molecular Engineering have devised a unique means of achieving effective gate operation with a form of information processing called electromagnonics. Their pivotal discovery allows real-time control of information transfer between microwave photons and magnons. And it could result in a new generation of classical electronic and quantum signal devices that can be used in various applications such as signal switching, low-power computing and quantum networking.
Microwave photons are elementary particles forming the electromagnetic waves employed in, for example, wireless communications. Magnons are the particle-like representatives of ?”spin waves.” That is, wave-like disturbances in an ordered array of microscopically aligned spins that occur in certain magnetic materials.
“Many research groups are combining different types of information carriers for information processing,” said Xufeng Zhang, assistant scientist in the Center for Nanoscale Materials, a DOE Office of Science User Facility at Argonne. “Such hybrid systems would enable practical applications that are not possible with information carriers of a single type.”
“Signal processing that couples spin waves and microwaves is a high-wire act,” added Zhang. “The signal must remain coherent despite energy dissipations and other outside effects threatening to throw the system into incoherence.”
Coherent gate operation (control over on, off and duration of the magnon-photon interaction) has been a long sought-after goal in hybrid magnonic systems. In principle, this can be achieved by rapid tuning of energy levels between the photon and magnon. However, such tuning has depended on changing the geometric configuration of the device. That typically requires much longer than the magnon lifetime — on the order of 100 nanoseconds (one-hundred billionths of a second). This lack of a rapid tuning mechanism for interacting magnons and photons has made it impossible to achieve any real-time gating control.
Using a novel method involving energy-level tuning, the team was able to rapidly switch between magnonic and photonic states over a period shorter than the magnon or photon lifetimes. This period is a mere 10 to 100 nanoseconds.
“We start by tuning the photon and magnon with an electric pulse so that they have the same energy level,” said Zhang. “Then, the information exchange starts between them and continues until the electric pulse is turned off, which shifts the energy level of the magnon away from that of the photon.”
By this mechanism, Zhang said, the team can control the flow of information so that it is all in the photon or all in the magnon or some place in between. This is made possible by a novel device design that allows nanosecond tuning of a magnetic field which controls the magnon energy level. This tunability allows the desired coherent gate operation.
This research points to a new direction for electromagnonics. Most importantly, the demonstrated mechanism not only works in the classical electronics regime, but can also be readily applied for manipulating magnonic states in the quantum regime. This opens opportunities for electromagnonics-based signal processing in quantum computing, communications and sensing.
Story Source:
Materials provided by DOE/Argonne National Laboratory. Original written by Joseph E. Harmon. Note: Content may be edited for style and length. More

An associate professor of marketing at The University of Texas at Arlington says digital avatars can replace a sales force and customer service employees at a fraction of the cost.
In this context, avatars are typically computer-generated representations of people. UTA Associate Professor Fred Miao says they can fill the void in interactive assistance that a majority of shoppers says they want.
“An Accenture survey of online shoppers shows that 62% never completed their purchases because there was no real-time customer service or support. That Accenture survey also shows that 90% of those shoppers wanted some sort of interactive assistance during the shopping process,” said Miao, faculty fellow of the John Merrill Endowed Professorship in Consultative Sales in UTA’s College of Business. “Avatars, used in the right way, can fill this void at a fraction of the cost of hiring and training human salespeople and service employees.”
Miao’s paper, “An Emerging Theory of Avatar Marketing,” appears in the Journal of Marketing, the premier research outlet for the American Marketing Association.
In his analysis, Miao argues that businesses using avatar representatives need to be on the lookout for misalignment between the form and behavioral realism of their avatars. Form realism relates to how much an avatar looks like a real human being. Behavioral realism relates to an avatar’s “intelligence” and whether it acts like a human being.
“Getting those two parts of an avatar matched is difficult,” Miao said. “When the physical and the behavioral aspects don’t synch up, the effectiveness of using avatars can be inconsistent and at best contingent upon the context, such as perceived financial risk.”
In complex relational exchanges with customers, such as when someone chooses a skincare product, avatars may be most effective when they are highly realistic looking and intelligent. When interactions involve privacy concerns, such as in mental health interviews, customers are better served with less realistic looking avatars that still act with intelligence.
Miao urges firms to consider five interrelated areas in using avatars: timing form realism behavioral realism form-behavioral realism alignment situational factors and context”The bottom line is that with budgets being so constricted among businesses, using avatars for marketing or customer service could not only be a worthwhile management tool to consider using, but also a means of increasing sales through consistent service quality,” Miao said.
Elten Briggs, chair and associate professor in the Department of Marketing, said Miao’s work conveys critical insights to businesses.
“Avatars and other forms of artificial intelligence are increasingly being employed to deliver services to customers,” Briggs said. “Dr. Miao’s paper provides much needed guidance on how businesses can utilize avatars to improve customers’ service experiences.”
Story Source:
Materials provided by University of Texas at Arlington. Note: Content may be edited for style and length. More

Each fingertip has more than 3,000 touch receptors, which largely respond to pressure. Humans rely heavily on sensation in their fingertips when manipulating an object. The lack of this sensation presents a unique challenge for individuals with upper limb amputations. While there are several high-tech, dexterous prosthetics available today — they all lack the sensation of “touch.” The absence of this sensory feedback results in objects inadvertently being dropped or crushed by a prosthetic hand.
To enable a more natural feeling prosthetic hand interface, researchers from Florida Atlantic University’s College of Engineering and Computer Science and collaborators are the first to incorporate stretchable tactile sensors using liquid metal on the fingertips of a prosthetic hand. Encapsulated within silicone-based elastomers, this technology provides key advantages over traditional sensors, including high conductivity, compliance, flexibility and stretchability. This hierarchical multi-finger tactile sensation integration could provide a higher level of intelligence for artificial hands.
For the study, published in the journal Sensors, researchers used individual fingertips on the prosthesis to distinguish between different speeds of a sliding motion along different textured surfaces. The four different textures had one variable parameter: the distance between the ridges. To detect the textures and speeds, researchers trained four machine learning algorithms. For each of the ten surfaces, 20 trials were collected to test the ability of the machine learning algorithms to distinguish between the ten different complex surfaces comprised of randomly generated permutations of four different textures.
Results showed that the integration of tactile information from liquid metal sensors on four prosthetic hand fingertips simultaneously distinguished between complex, multi-textured surfaces — demonstrating a new form of hierarchical intelligence. The machine learning algorithms were able to distinguish between all the speeds with each finger with high accuracy. This new technology could improve the control of prosthetic hands and provide haptic feedback, more commonly known as the experience of touch, for amputees to reconnect a previously severed sense of touch.
“Significant research has been done on tactile sensors for artificial hands, but there is still a need for advances in lightweight, low-cost, robust multimodal tactile sensors,” said Erik Engeberg, Ph.D., senior author, an associate professor in the Department of Ocean and Mechanical Engineering and a member of the FAU Stiles-Nicholson Brain Institute and the FAU Institute for Sensing and Embedded Network Systems Engineering (I-SENSE), who conducted the study with first author and Ph.D. student Moaed A. Abd. “The tactile information from all the individual fingertips in our study provided the foundation for a higher hand-level of perception enabling the distinction between ten complex, multi-textured surfaces that would not have been possible using purely local information from an individual fingertip. We believe that these tactile details could be useful in the future to afford a more realistic experience for prosthetic hand users through an advanced haptic display, which could enrich the amputee-prosthesis interface and prevent amputees from abandoning their prosthetic hand.”
Researchers compared four different machine learning algorithms for their successful classification capabilities: K-nearest neighbor (KNN), support vector machine (SVM), random forest (RF), and neural network (NN). The time-frequency features of the liquid metal sensors were extracted to train and test the machine learning algorithms. The NN generally performed the best at the speed and texture detection with a single finger and had a 99.2 percent accuracy to distinguish between ten different multi-textured surfaces using four liquid metal sensors from four fingers simultaneously.
“The loss of an upper limb can be a daunting challenge for an individual who is trying to seamlessly engage in regular activities,” said Stella Batalama, Ph.D., dean, College of Engineering and Computer Science. “Although advances in prosthetic limbs have been beneficial and allow amputees to better perform their daily duties, they do not provide them with sensory information such as touch. They also don’t enable them to control the prosthetic limb naturally with their minds. With this latest technology from our research team, we are one step closer to providing people all over the world with a more natural prosthetic device that can ‘feel’ and respond to its environment.”
Story Source:
Materials provided by Florida Atlantic University. Original written by Gisele Galoustian. Note: Content may be edited for style and length. More

Feeling extra sweaty from a summer heat wave? Don’t worry — not all your perspiration has to go to waste. In a paper publishing July 13 in the journal Joule, researchers have developed a new device that harvests energy from the sweat on — of all places — your fingertips. To date, the device is the most efficient on-body energy harvester ever invented, producing 300 millijoules (mJ) of energy per square centimeter without any mechanical energy input during a 10-hour sleep and an additional 30 mJ of energy with a single press of a finger. The authors say the device represents a significant step forward for self-sustainable wearable electronics.
“Normally, you want maximum return on investment in energy. You don’t want to expend a lot of energy through exercise to get only a little energy back,” says senior author Joseph Wang (@JWangnano), a nanoengineering professor at the University of California San Diego. “But here, we wanted to create a device adapted to daily activity that requires almost no energy investment — you can completely forget about the device and go to sleep or do desk work like typing, yet still continue to generate energy. You can call it ‘power from doing nothing.'”
Previous sweat-based energy devices required intense exercise, such as a great deal of running or biking, before the user sweated enough to activate power generation. But the large amount of energy consumed during exercise can easily cancel out the energy produced, often resulting in energy return on investment of less than 1%.
In contrast, this device falls into what the authors call the “holy grail” category of energy harvesters. Instead of relying on external, irregular sources like sunlight or movement, all it needs is finger contact to collect more than 300 mJ of energy during sleep — which the authors say is enough to power some small wearable electronics. Since no movement is needed, the ratio between harvested energy and invested energy is essentially infinite.
It may seem odd to choose fingertips as the source of this sweat over, say, the underarms, but in fact, fingertips have the highest concentration of sweat glands compared to anywhere else on the body.
“Generating more sweat at the fingers probably evolved to help us better grip things,” says first co-author Lu Yin (@YinLu_CLT), a nanoengineering PhD student working in Wang’s lab. “Sweat rates on the finger can reach as high as a few microliters per square centimeter per minute. This is significant compared to other locations on the body, where sweat rates are maybe two or three orders of magnitude smaller.”
The device the researchers developed in this study is a type of energy harvester called a biofuel cell (BFC) and is powered by lactate, a dissolved compound in sweat. From the outside, it looks like a simple piece of foam connected to a circuit with electrodes, all of which is attached to the pad of a finger. The foam is made out of carbon nanotube material, and the device also contains a hydrogel that helps maximize sweat absorption.
“The size of the device is about 1 centimeter squared. Its material is flexible as well, so you don’t need to worry about it being too rigid or feeling weird. You can comfortably wear it for an extended period of time,” says Yin.
Within the device, a series of electrochemical reactions occur. The cells are equipped with a bioenzyme on the anode that oxidizes, or removes electrons from, the lactate; the cathode is deposited with a small amount of platinum to catalyze a reduction reaction that takes the electron to turn oxygen into water. Once this happens, electrons flow from the lactate through the circuit, creating a current of electricity. This process occurs spontaneously: as long as there is lactate, no additional energy is needed to kickstart the process.
Separate from but complementary to the BFC, piezoelectric generators — which convert mechanical energy into electricity — are also attached to the device to harvest up to 20% additional energy. Relying on the natural pinching motion of fingers or everyday motions like typing, these generators helped produce additional energy from barely any work: a single press of a finger once per hour required only 0.5 mJ of energy but produced over 30 mJ of energy, a 6,000% return in investment.
The researchers were able to use the device to power effective vitamin C- and sodium-sensing systems, and they are optimistic about improving the device to have even greater abilities in the future, which might make it suitable for health and wellness applications such as glucose meters for people with diabetes. “We want to make this device more tightly integrated in wearable forms, like gloves. We’re also exploring the possibility of enabling wireless connection to mobile devices for extended continuous sensing,” Yin says.
“There’s a lot of exciting potential,” says Wang. “We have ten fingers to play with.”
Story Source:
Materials provided by Cell Press. Note: Content may be edited for style and length. More

Scientists at Tokyo Institute of Technology have developed a computational method based on large-scale molecular dynamics simulations to predict the cell-membrane permeability of cyclic peptides using a supercomputer. Their protocol has exhibited promising accuracy and may become a useful tool for the design and discovery of cyclic peptide drugs, which could help us reach new therapeutic targets inside cells beyond the capabilities of conventional small-molecule drugs or antibody-based drugs.
Cyclic peptide drugs have attracted the attention of major pharmaceutical companies around the world as promising alternatives to conventional small molecule-based drugs. Through proper design, cyclic peptides can be tailored to reach specific targets inside cells, such as protein-protein interactions, which are beyond the scope of small molecules. Unfortunately, it has proven notoriously difficult to design cyclic peptides with high cell-membrane permeability — that is, cyclic peptides that can easily diffuse through the lipid bilayer that delimits the inside and outside of a cell.
In an effort to resolve this bottleneck, scientists at the Middle Molecule IT-based Drug Discovery Laboratory (MIDL) have been working on a computational method for predicting cell-membrane permeability. Established in September 2017, MIDL is one of the “Research Initiatives” at Tokyo Institute of Technology (Tokyo Tech) that goes beyond the boundaries of departments. Under the support of the Program for Building Regional Innovation Ecosystems of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), MIDL has been working with the city of Kawasaki to industrialize a framework for discovering middle molecule-based drugs — cyclic peptide drugs and nucleic acid drugs larger than conventional small-molecule drugs but smaller than antibody-based drugs — by combining computational drug design and chemical synthesis technology.
In a recent study published in the Journal of Chemical Information and Modeling, Professor Yutaka Akiyama and colleagues from MIDL and Tokyo Tech have developed a protocol for predicting the cell-membrane permeability of cyclic peptides using molecular dynamics simulations. Such simulations constitute a widely accepted computational approach for predicting and reproducing the dynamics of atoms and molecules by sequentially solving Newton’s laws of motion at short time intervals. However, even a single simulation for predicting the permeability of a cyclic peptide with only eight amino acids takes a tremendous amount of time and resources. “Our study marks the first time comprehensive simulations were performed for as many as 156 different cyclic peptides,” highlights Prof. Akiyama, “The simulation of each cyclic peptide using the protocol we developed took about 70 hours per peptide using 28 GPUs on the TSUBAME 3.0 supercomputer at Tokyo Tech.”
The researchers verified the predicted permeability values with experimentally derived ones and confirmed an acceptable correlation coefficient of R = 0.63 under the best conditions, showcasing the potential of their protocol. Moreover, after a detailed analysis of the peptide conformation and energy values obtained from the trajectory data, Prof. Akiyama’s team found that the strength of the electrostatic interactions between the atoms constituting the cyclic peptide and the surrounding media, namely lipid membrane and water molecules, are strongly related to the membrane permeability value. The simulations also revealed the way in which peptides permeate through the membrane by changing their orientation and conformation according to their surroundings. “Our results shed some light on the mechanisms of cell-membrane permeability and provide a guideline for designing molecules that can get inside cells more efficiently. This will greatly contribute to the development of next-generation peptide drugs,” remarks Prof. Masatake Sugita, the first author of the study.
The researchers are already working on a more advanced simulation protocol that will enable more accurate predictions. They are also trying to incorporate artificial intelligence into the picture by adopting deep learning techniques, which could increase both accuracy and speed. Considering that cyclic peptides could unlock many therapeutic targets for diseases that are difficult to treat, let us hope that scientists at MIDL and Tokyo Tech succeed in their endeavors!
Story Source:
Materials provided by Tokyo Institute of Technology. Note: Content may be edited for style and length. More

The absorption of energy from laser light by free electrons in a liquid has been demonstrated for the first time. Until now, this process was observed only in the gas phase. The findings, led by Graz University of Technology, open new doors for ultra-fast electron microscopy.
The investigation and development of materials crucially depends on the ability to observe smallest objects at fastest time scales. The necessary spatial resolution for investigations in the (sub-)atomic range can be achieved with electron microscopy. For the most rapid processes, however, proceeding within a few femtoseconds (quadrillionths of a second), the time resolution of conventional electron microscopes is insufficient. To improve the time duration of electron pulses, electrons would have to be selected within a shorter time window — in analogy to a camera shutter, which controls the exposure time in photography.
In principle, this temporal selection is possible with extremely short laser pulses through a process called laser-assisted electron scattering (LAES). In this process, electrons can absorb energy from the light field during collisions with atoms of the sample under investigation. “Structural information is provided by all electrons, but those that have a higher energy level can be assigned to the time window in which the light pulse was present. With this method, it is possible to select a short time window from the long electron pulse and thus improve the time resolution,” explains Markus Koch, professor at the Institute of Experimental Physics at Graz University of Technology. So far, however, LAES processes have only been observed in the gas phase, despite their investigation for about 50 years.
Markus Koch and his team, in collaboration with researchers from Photonics Institute at Vienna University of Technology and the Institute of Chemistry at Tokyo Metropolitan University, have now demonstrated for the first time that laser-assisted electron scattering can also be observed in condensed matter, specifically in superfluid helium.
Superfluid helium leading to success
The TU Graz researchers performed the experiment in a superfluid helium droplet of few nanometer diameter (3-30 nm), into which they loaded single atoms (indium or xenon) or molecules (acetone) that served as an electron source — a field of expertise at the institute. “The free electrons can move almost without friction within the droplet and absorb more energy in the light field than they lose in collisions with the helium atoms,” says Leonhard Treiber, the PhD student in charge of the experiment. The resulting acceleration allows for the observation of much faster electrons.
The experiments could be interpreted in cooperation with Markus Kitzler-Zeiler, an expert for strong-field processes at TU Wien, and the LAES process was confirmed through simulations by Reika Kanya from Tokyo Metropolitan University. The results were published in Nature Communications.
In the future, the LAES process will be studied within thin films of various materials, also produced inside helium droplets, in order to determine important parameters such as the optimal film thickness or the favourable intensity of the laser pulses for application in an electron microscope.
Story Source:
Materials provided by Graz University of Technology. Original written by Christoph Pelzl. Note: Content may be edited for style and length. More