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A research team has developed a new range of strain sensors that are 10 times more sensitive when measuring minute movements. These sensors are ultra-thin, battery-free and can transmit data wirelessly, making them attractive for a wide range of applications. More
A research group is defining a new sub-area of mobile technology that they call ‘earable computing.’ The team believes that earphones will be the next significant milestone in wearable devices, and that new hardware, software, and apps will all run on this platform. More
Is it possible to read a person’s mind by analyzing the electric signals from the brain? The answer may be much more complex than most people think.
Purdue University researchers — working at the intersection of artificial intelligence and neuroscience — say a prominent dataset used to try to answer this question is confounded, and therefore many eye-popping findings that were based on this dataset and received high-profile recognition are false after all.
The Purdue team performed extensive tests over more than one year on the dataset, which looked at the brain activity of individuals taking part in a study where they looked at a series of images. Each individual wore a cap with dozens of electrodes while they viewed the images.
The Purdue team’s work is published in IEEE Transactions on Pattern Analysis and Machine Intelligence. The team received funding from the National Science Foundation.
“This measurement technique, known as electroencephalography or EEG, can provide information about brain activity that could, in principle, be used to read minds,” said Jeffrey Mark Siskind, professor of electrical and computer engineering in Purdue’s College of Engineering. “The problem is that they used EEG in a way that the dataset itself was contaminated. The study was conducted without randomizing the order of images, so the researchers were able to tell what image was being seen just by reading the timing and order information contained in EEG, instead of solving the real problem of decoding visual perception from the brain waves.”
The Purdue researchers originally began questioning the dataset when they could not obtain similar outcomes from their own tests. That’s when they started analyzing the previous results and determined that a lack of randomization contaminated the dataset.
“This is one of the challenges of working in cross-disciplinary research areas,” said Hari Bharadwaj, an assistant professor with a joint appointment in Purdue’s College of Engineering and College of Health and Human Sciences. “Important scientific questions often demand cross-disciplinary work. The catch is that, sometimes, researchers trained in one field are not aware of the common pitfalls that can occur when applying their ideas to another. In this case, the prior work seems to have suffered from a disconnect between AI/machine-learning scientists, and pitfalls that are well-known to neuroscientists.”
The Purdue team reviewed publications that used the dataset for tasks such as object classification, transfer learning and generation of images depicting human perception and thought using brain-derived representations measured through electroencephalograms (EEGs)
“The question of whether someone can read another person’s mind through electric brain activity is very valid,” said Ronnie Wilbur, a professor with a joint appointment in Purdue’s College of Health and Human Sciences and College of Liberal Arts. “Our research shows that a better approach is needed.”
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Materials provided by Purdue University. Original written by Chris Adam. Note: Content may be edited for style and length. More
A team of New Jersey researchers has shown that gait training using robotic exoskeletons improved motor function in adolescents and young adults with acquired brain injury. The article, “Kinetic gait changes after robotic exoskeleton training in adolescents and young adults with acquired brain injury” was published October 28, 2020 in Applied Bionics and Biomechanics.
The authors are Kiran Karunakaran, PhD, Naphtaly Ehrenberg, MS, and Karen Nolan, PhD, from the Center for Mobility and Rehabilitation Engineering Research at Kessler Foundation, and JenFu Cheng, MD, and Katherine Bentley, MD, from Children’s Specialized Hospital. Drs. Karunakaran, Nolan, Cheng, and Bentley are also affiliated with the Department of Physical Medicine and Rehabilitation at Rutgers New Jersey Medical School.
Acquired brain injury often results in hemiparesis, causing significant deficits in balance and gait that adversely affect functional ambulation and participation in activities of daily living. Gait training using robotic exoskeletons offers an option for motor rehabilitation in individuals with hemiparesis, but few studies have been conducted in adolescents and young adults. Findings from a preliminary study in this age group show promise for this intervention, according to Drs. Karunakaran and Nolan.
Participants included seven individuals (aged 13 to 28 years) with acquired brain injury (ABI) and hemiparesis and one healthy control. The ABI group included individuals with brain injuries due to anoxia, trauma, and stroke. All participants received 12 45-minute sessions of high-dose, repetitive gait training in a robotic exoskeleton (EksoGT, Ekso Bionics, Inc.) over a 4-week period. The gait training was administered by a licensed physical therapist supervised by a member of the research team.
“At the end of the 4-week training, participants had progressed to a more normal gait pattern,” said Dr. Karunakaran, “including improved loading, a longer step length and faster walking speed” Although results are promising, Dr. Nolan acknowledged the limitations of the study, including small sample size and lack of a control group: “Further study is needed to confirm the training effect in this age group with ABI, optimal dosing for the training protocol, and the durability of functional improvements.”
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Materials provided by Kessler Foundation. Note: Content may be edited for style and length. More
Scientists at the University of Bath have developed a quick and easy approach for capturing 360° VR photography without using expensive specialist cameras. The system uses a commercially available 360° camera on a rotating selfie stick to capture video footage and create an immersive VR experience.
Virtual reality headsets are becoming increasingly popular for gaming, and with the global pandemic restricting our ability to travel, this system could also be a cheap and easy way to create virtual tours for tourist destinations.
Conventional 360° photography stitches together thousands of shots as you move around one spot. However, it doesn’t retain depth perception, so the scene is distorted and the images look flat.
Whilst state-of-the-art VR photography, which includes depth perception, is available to professional photographers, it requires expensive equipment, as well as time to process the thousands of photos needed to create a fully immersive VR environment.
Dr Christian Richardt and his team at CAMERA, the University of Bath’s motion capture research centre, have created a new type of 360° VR photography accessible to amateur photographers called OmniPhotos.
This is a fast, easy and robust system that recreates high quality motion parallax, so that as the VR user moves their head, the objects in the foreground move faster than the background.
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This mimics how your eyes view the real world, creating a more immersive experience.
OmniPhotos can be captured quickly and easily using a commercially available 360° video camera on a rotating selfie stick.
Using a 360° video camera also unlocks a significantly larger range of head motions.
OmniPhotos are built on an image-based representation, with optical flow and scene adaptive geometry reconstruction, which is tailored for real time 360° VR rendering.
Dr Richardt and his team presented the new system at the international SIGGRAPH Asia conference on Sunday 13th December 2020.
He said: “Until now, VR photography that uses realistic motion parallax has been the preserve of professional VR photographers, using expensive equipment and requiring complex software and computing power to process the images.
“OmniPhotos simplifies this process so that you can use it with a commercially available 360° camera that only costs a few hundred pounds.
“This opens up VR photography to a whole new set of applications, from estate agent’s virtual tours of houses to immersive VR journeys at remote tourist destinations. With the pandemic stopping many people from travelling on holiday this year, this is a way of virtually visiting places that are currently inaccessible.”
Further information: https://richardt.name/publications/omniphotos/
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Materials provided by University of Bath. Note: Content may be edited for style and length. More
Electrons inhabit a strange and topsy-turvy world. These infinitesimally small particles have never ceased to amaze and mystify despite the more than a century that scientists have studied them. Now, in an even more amazing twist, physicists have discovered that, under certain conditions, interacting electrons can create what are called “topological quantum states.” This finding, which was recently published in the journal Nature, has implications for many technological fields of study, especially information technology.
Topological states of matter are particularly intriguing classes of quantum phenomena. Their study combines quantum physics with topology, which is the branch of theoretical mathematics that studies geometric properties that can be deformed but not intrinsically changed. Topological quantum states first came to the public’s attention in 2016 when three scientists — Princeton’s Duncan Haldane, who is Princeton’s Thomas D. Jones Professor of Mathematical Physics and Sherman Fairchild University Professor of Physics, together with David Thouless and Michael Kosterlitz — were awarded the Nobel Prize for their work in uncovering the role of topology in electronic materials.
“The last decade has seen quite a lot of excitement about new topological quantum states of electrons,” said Ali Yazdani, the Class of 1909 Professor of Physics at Princeton and the senior author of the study. “Most of what we have uncovered in the last decade has been focused on how electrons get these topological properties, without thinking about them interacting with one another.”
But by using a material known as magic-angle twisted bilayer graphene, Yazdani and his team were able to explore how interacting electrons can give rise to rise to surprising phases of matter.
The remarkable properties of graphene were discovered two years ago when Pablo Jarillo-Herrero and his team at the Massachusetts Institute of Technology (MIT) used it to induce superconductivity — a state in which electrons flow freely without any resistance. The discovery was immediately recognized as a new material platform for exploring unusual quantum phenomena.
Yazdani and his fellow researchers were intrigued by this discovery and set out to further explore the intricacies of superconductivity.
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But what they discovered led them down a different and untrodden path.
“This was a wonderful detour that came out of nowhere,” said Kevin Nuckolls, the lead author of the paper and a graduate student in physics. “It was totally unexpected, and something we noticed that was going to be important.”
Following the example of Jarillo-Herrero and his team, Yazdani, Nuckolls and the other researchers focused their investigation on twisted bilayer graphene.
“It’s really a miracle material,” Nuckolls said. “It’s a two-dimensional lattice of carbon atoms that’s a great electrical conductor and is one of the strongest crystals known.”
Graphene is produced in a deceptively simple but painstaking manner: a bulk crystal of graphite, the same pure graphite in pencils, is exfoliated using sticky tape to remove the top layers until finally reaching a single-atom-thin layer of carbon, with atoms arranged in a flat honeycomb lattice pattern.
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To get the desired quantum effect, the Princeton researchers, following the work of Jarillo-Herrero, placed two sheets of graphene on top of each other with the top layer angled slightly. This twisting creates a moiré pattern, which resembles and is named after a common French textile design. The important point, however, is the angle at which the top layer of graphene is positioned: precisely 1.1 degrees, the “magic” angle that produces the quantum effect.
“It’s such a weird glitch in nature,” Nuckolls said, “that it is exactly this one angle that needs to be achieved.” Angling the top layer of graphene at 1.2 degrees, for example, produces no effect.
The researchers generated extremely low temperatures and created a slight magnetic field. They then used a machine called a scanning tunneling microscope, which relies on a technique called “quantum tunneling” rather than light to view the atomic and subatomic world. They directed the microscope’s conductive metal tip on the surface of the magic-angle twisted graphene and were able to detect the energy levels of the electrons.
They found that the magic-angle graphene changed how electrons moved on the graphene sheet. “It creates a condition which forces the electrons to be at the same energy,” said Yazdani. “We call this a ‘flat band.'”
When electrons have the same energy — are in a flat band material — they interact with each other very strongly. “This interplay can make electrons do many exotic things,” Yazdani said.
One of these “exotic” things, the researchers discovered, was the creation of unexpected and spontaneous topological states.
“This twisting of the graphene creates the right conditions to create a very strong interaction between electrons,” Yazdani explained. “And this interaction unexpectedly favors electrons to organize themselves into a series of topological quantum states.”
Specifically, they discovered that the interaction between electrons creates what are called topological insulators. These are unique devices that act as insulators in their interiors, which means that the electrons inside are not free to move around and therefore do not conduct electricity. However, the electrons on the edges are free to move around, meaning they are conductive. Moreover, because of the special properties of topology, the electrons flowing along the edges are not hampered by any defects or deformations. They flow continuously and effectively circumvent the constraints — such as minute imperfections in a material’s surface — that typically impede the movement of electrons.
During the course of the work, Yazdani’s experimental group teamed up two other Princetonians — Andrei Bernevig, professor of physics, and Biao Lian, assistant professor of physics — to understand the underlying physical mechanism for their findings.
“Our theory shows that two important ingredients — interactions and topology — which in nature mostly appear decoupled from each other, combine in this system,” Bernevig said. This coupling creates the topological insulator states that were observed experimentally.
Although the field of quantum topology is relatively new, it holds great potential for revolutionizing the areas of electrical engineering, materials science and especially computer science.
“People talk a lot about its relevance to quantum computing, where you can use these topological quantum states to make better types of quantum bits,” Yazdani said. “The motivation for what we’re trying to do is to understand how quantum information can be encoded inside a topological phase. Research in this area is producing exciting new science and can have potential impact in advancing quantum information technologies.”
Yazdani and his team will continue their research into understanding how the interactions of electrons give rise to different topological states.
“The interplay between the topology and superconductivity in this material system is quite fascinating and is something we will try to understand next,” Yazdani said. More
Researchers have fabricated transparent, ultrathin, flexible sensors with cross-aligned silver nanowire microelectronics fabricated using print technique that would be inexpensive and straightforward to mass-produce. This advance will find much use in biometrics and many other applications that require underlying visual observation. More
Since the 2019/20 season, controversial referee calls in the English Premier League may be technically reviewed and, if deemed necessary, corrected. Using a Twitter analysis of 129 games in the English Premier League, a research team from the Technical University of Munich (TUM) has now determined how decisions made by video referees affect the mood of the fans.
For its 2019/20 season, the English Premier League introduced the video assistant referee (VAR). Dr. Otto Kolbinger and Melanie Knopp from the Chair of Performance Analysis and Sports Informatics at the Technical University of Munich have now investigated the extent to which this influences the mood of audiences.
A total of 643,251 English-language tweets from the social media channel Twitter were included in the study, which investigated 94 VAR incidents from 129 games. Of these, over 58,000 tweets (9.1 percent) were directly related to the video referee.
Analyzing Twitter tweets using artificial intelligence
For their analysis, the team employed “text mining,” an algorithm-based analysis process which unearths structures of meaning buried in text data. The study focused on the automatic extraction of tacit knowledge from large amounts of text data, in this case tweets, collected via an interface.
“We used the official hashtag for each game to ensure that the tweets really refer to the game in question,” explained Dr. Kolbinger, elucidating the procedure. “We also, for the first time ever, used a new text classification algorithm. In our case, it performed better than algorithms used in previous studies.”
To avoid so-called overfitting — the over-adaptation of a model to a given data set — the team allowed only a fraction of the variables to flow into each individual step during model fitting.
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The use of video assistants kill the mood
In its data analysis, the team examined whether tweets referring to a specific VAR situation are formulated positively or negatively. They found that the average sentiment of tweets relating to decisions by the video referee was significantly lower than that of other tweets: 76.24 percent of the 58,000 tweets were negative, 12.33 percent positive and 11.43 percent neutral.
The research team also examined the average sentiment of all tweets for a given match chronologically. It turns out that the mood of tweets published after a VAR incident is significantly worse than that of tweets published before the incident.
This slump lasted 20 minutes on average. Deploying VAR in a match produces a negative sentiment on Twitter. It was this realization that led to the striking study title, rich in associations: “Video kills the sentiment.”
More transparent communication of VAR decisions
According to the researchers the status quo is unsatisfactory, which is why they are calling on the governing bodies of the European football associations and leagues to improve the system.
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“The football associations should attempt to communicate all VAR decisions with greater transparency,” recommends Dr. Kolbinger. “To ensure this transparency, the associations could broadcast the communications between the referee on the field and the video referee, as it is done in field hockey. An alternative would be to introduce the option of a ‘coaches challenge’, as in American football. But this is all just food for thought, based on our results.”
Assess audience responses quantitatively and qualitatively
“The research project led by Dr. Otto Kolbinger and Melanie Knopp is a pioneering achievement,” says Prof. Lames, who heads the Chair of Performance Analysis and Sports Informatics. “They deployed a technology that they developed and applied for the first time in Germany. It is an innovative and groundbreaking contribution that advances science in this area. ”
“These sentiment analyzes can be used to measure reactions from audiences both quantitatively and qualitatively,” explains Prof. Lames. “In addition, we can investigate assessments and emotions, which is an extremely valuable marketing tool.” More
