Using Muscle Activity To Control Machines

Independent living is important to everyone. However, it is a known fact that there are many cases where physical problems prevent people from living without care. To help people regain some independence in their lives there are systems such as Human to Machine Interfaces (HMI). Systems such as these work by using biosignals like Electromyographic (EMG) signals that can be used to control assistive devices. However, some have their drawbacks: prosthetic arms, for instance, are one commonly used device that are at times abandoned due to a lack of dexterity and precision.

The problem is that most of these devices make use of sequential control, where only one function can be articulated at a time— meaning fluid, life-like motions are impossible. Now, most daily activities need simultaneous movement with multiple degrees of freedom. And it is this need that is pushing the creators of these devices to create simultaneous control to mimic real life movements.

Christian Grech (supervised by Dr Tracey Camilleri and co-supervised by Dr Ing. Marvin Bugeja) has developed a system which allows the control of the position of a robotic arm by using the muscle activity of a person. This consists of an HMI which continuously provides the shoulder and elbow joint positions using surface muscle movements. Grech tested the model to develop more freedom, which would lead to fluid movements. He investigated three types of system identification methods (state space models, linear regression models, and neural networks) to develop this relationship between muscle activity and corresponding joint angles. Additionally, seven different movements were tested in real-time using a robotic arm. Grech managed to develop a model that allows prosthetic arms to be used more naturally.

Of course, more research is needed to perfect this device. Ideally it would operate without delay and with minimal user discomfort. The Department of Systems & Control Engineering is carrying out more research to continue to improve the accuracy and robustness of such myoelectric (EMG) controlled devices.

This research was carried out as part of a Bachelor of Engineering degree at the Faculty of Engineering, University of Malta.

How To Teach Quantum Physics To Your Dog

Book review by Andrea Marie Cini

The term quantum physics has struck fear into many hearts. Such a complex subject has, for many years, dumbfounded students, and, it seems, their dogs alike. Chad Orzel (a professor at Union College,New York) in his book, How To Teach Quantum Physics To Your Dog, tries to accomplish just that; how do you explain sub-atomic physics in a fun and easy way? Using his dog Emmy as a fellow narrator, Orzel explains quantum physics from a different, more canine-oriented perspective, and actually manages to make it work!

Making use of situations that dogs encounter on a nearly daily basis, such as rabbit chasings, evil squirrels and squeaky toys, the author explains some of the most complex theories and experiments in science. Sound bites as particle-wave duality, Heisenberg’s uncertainty principle, and quantum tunnelling are just a few of the many topics covered and are colourfully explained within this book. Making use of simple diagrams and modern references, these previously baffling topics are simplified in a way even a dog could understand (if dogs were capable of learning science—debatable). Orzel’s ideology is pretty simple: if a dog could understand his explanations then a human surely would.

Apart from being a sturdy foundation for the topic of quantum physics, the fun-loving and comical conversations between Orzel and Emmy the dog are a captivating read. Emmy’s curious questions and Orzel’s exceptionally patient answers make it almost impossible for readers to forget. Within this novel it feels as if the reader is really strolling in a park with the duo. Apart from this professor’s incredible explanations and handy diagrams, another distinguishable feature of his book is the fascinating footnotes—a source of unforgettable fun facts. For example, did you know that the great scientist, Schrödinger, was a notorious womaniser?

While I would not recommend How To Teach Quantum Physics To Your Dog to pass the next quantum mechanics exam, it is great foundation material. Studying quantum physics has never been more fun and the book is a great read—highly recommended.

Galactic rotation dynamics in modified gravity

In the last 100 years, Einstein’s theory of general relativity has proven invaluable to explain the nature of the universe. That being said, Einstein’s model of gravity does at times fail to comply with what we actually observe when looking up at the night sky.

Galaxies offer one of the most impressive laboratories where general relativity just does not work. Stellar objects in galaxies tend to orbit the galactic centre of mass. General relativity predicts that as one goes further from the centre of the galaxy, these orbital speeds drop off. Observational data shows that these velocities tend to stay constant along the radius of a galaxy. However, dark matter can be artificially introduced to account for this. The other argument is that such failures indicate the inability of general relativity to fully explain how the universe works. If this is so, it seems necessary to construct what are called alternative or modified theories of gravity. Such theories would have to be capable of correctly explaining all observed phenomena including those that general relativity fails to produce.

Andrew Finch (supervised by Dr Jackson Levi Said) is looking into the new concept of treating gravity as a torsional dominated system instead of a curvature dominated one, which is the concept explained by general relativity. The new models are being developed with the intention of agreeing with galactic rotation curves while managing to explain everything that general relativity already does. It is only possible to vigorously test such models because of the large amount of freely available data which has been gathered on galaxies. As models are obtained, the cluster in the ISSA (Institute of Space Science and Astronomy) laboratory is being used in order to determine model parameters. Using this data, Finch aims to compare Einstein’s theory with the new model being developed. Will it improve on Einstein’s ideas? Only Finch will tell…

This research is being performed as part of a Masters Degree in Astrophysics being read at the Institute of Space Sciences and Astronomy, University of Malta.

Andrew Finch

Special Feature – The Maltese Genome

DNA is what life is made of. Found in every cell of the human body, it has sent criminals to jail and been the focus of controversial court cases. Dr Jean Buttigieg discusses these legal and ethical issues. DNA has also transformed the meaning of being human, with traits from disease to intelligence all linked to it. DNA is changing the world.

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Octopus around Malta: Safe to eat?

Heavy metals can be toxic to humans. They need to be monitored to ensure environmental levels do not go above dangerous levels. The European Commission has set acceptable maximum levels of metals allowed in food since most metals end up in humans through their diet.

But how do metals find their way into our food in the first place? Heavy metals can enter the environment in a number of ways, including through volcanism, fossil fuel burning, and antifouling paint use. The heavy metals bind with biomolecules inside living tissue, and can build up to dangerous levels. One prime example of how such metals end up in the food we eat can be seen in the case of the common octopus (Octopus vulgaris). The octopus is susceptible to accumulating high levels of heavy metals due to its high ingestion rate of benthic fauna.

Joshua Gili (supervised by Prof. Victor Axiak) recorded the concentrations of cadmium, copper, lead, and zinc in the common octopus. Specimens were collected from around Malta during summer and winter. The analysis was performed on two of the species’ tissues—the tentacles and the digestive glands— which function in a similar way to the human liver. Each tissue was gathered into one pool by site, then homogenised, dried, and acid-treated. Afterwards a technique called polarography was used to determine the levels of each metal. This data helped Gili decide whether metal accumulation in the tissue of octopi is affected by biometry, season, or geography.

In Malta, metal levels depended on where the octopus was caught. In general, the concentrations were lower than other Mediterranean regions. The levels of cadmium and lead in the tentacles were below toxic levels as stated by the European Commission, indicating that local octopus is safe to eat.

This research was performed as part of Joshua Gili’s Bachelor of Science (Honours) in Biology and Chemistry, which he is reading at the Faculty of Science, University of Malta.

Blood, Genes, and You

Over the course of nine months, an entire human body is sculpted from a few cells into a baby. The blueprint is the information written into our DNA. But what happens if there is a mistake in these blueprints? Decades worth of research carried out in Malta and abroad have aimed to understand how these errors lead to a disease common in Malta and prevalent worldwide.
Scott Wilcockson talks to Dr Joseph Borg (Faculty of Health Sciences, University of Malta) to find out more.

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