I am happy to announce that I have been awarded a new EPSRC grant – technically it is UKRI & RCN (Research Council of Norway) project – UKRI-RCN: Exploiting the dynamics of self-timed machine learning hardware (ESTEEM).
I am very excited to work on it with my two Newcastle colleagues Rishad Shafik and Domenico Balsamo, Uni of Agder colleague Ole-Christoffer Granmo, and in close collaboration with PragmatIC, Mignon and CFT.
More details on this project can be found here.
I had a pleasure to present a keynote talk at the 13th International Conference Dependable Systems, Services and Technologies (DESSERT 2023), held in Greece, Athens, October 13-15, 2023, in a hybrid mode.
The talk’s topic was “Tsetlin Machines: stepping towards energy-efficient, explainable and dependable AI” https://www.dessert-conf.org/dessert-2023/alex-yakovlev/
The PDF of the slides can be found here
Victor Ilyich Varshavsky was born today, on 23rd February, 90 years ago. Victor Varshavsky is a pioneer of automata theory, aperiodic (aka self-timed) circuits and systems https://en.wikipedia.org/wiki/Asynchronous_circuit, and collective behaviour of automata. In the 1960s, being a close colleague and friend of Mikhail Tsetlin, Victor laid foundation to the theory of learning automata and machine intelligence, which find their way today to modern methods of machine learning – such as Tsetlin Machine: https://en.wikipedia.org/wiki/Tsetlin_machine
You can read about Victor Varshavsky’s contributrions in this document:https://web.cecs.pdx.edu/~mperkows/CLASS_573/Asynchr_Febr_2007/M.pdf
I am immensely proud to be one of his disciples.
Last week I gave a public lecture “”Data-driven computing (or Liberating computing from memory walls)”, at Technical University of Vienna, Austria, where I am acting as Guest Professor for 2022.
The lecture was on my relatively recent ideas of bringing machine learning into computing at different scales and levels of abstraction, basically making it a commodity that can be introduced for improving the quality of computing from many aspects, in particular performance and use of energy.
The advert of the lecture can be found here: https://informatics.tuwien.ac.at/news/2199
There is also a recording of the lecture available here: https://tube1.it.tuwien.ac.at/w/ebJrRwrJP2ozpsoWAyfy3T
Together with Alex Ventisei and Victor Pacheco-Pena, we recently published a paper that for the first time connects the world of electromagnetic waves with the graphical modelling language of Petri nets. https://onlinelibrary.wiley.com/doi/10.1002/adts.202100429
Petri nets are known to capture in a very natural for comprehension form ideas of causality, concurrency and choice. The way how the Petri nets primitives – transitions (bars or boxes), places (circles), flow relation between them (arcs between places and transitions and between transitions and places), and marking of places (tokens) – can ‘speak’ in the languages of EM pulses propagating in transmission lines and interacting in their cross-points is quite interesting. For example, firstly, due to the fact that EM or to be precise TEM pulses cannot wait for each other in the points of crossing, is expressed in the corresponding Petri nets by the fact that we have not multiple incidence of flows on the same transition. In other words, we cannot have AND causality in TEM switching structures. On the other hand, secondly, due to the physical superposition of TEM pulses travelling from different sources, we have a pure effect of OR causality, manifested itself in the Petri nets having multiple incidence of flows of tokens on the same place. Thirdly, the fact that pulses are propagated and reflected in the points of crossing according to the proportions dictated by the impedance rations, represented by the scattering matrices, is manifested in the Petri net model by the corresponding fractioning and additions of tokens in places standing for these pulse interactions.
The type of Petri nets characterising TEM pulse interaction is fairly unique and is worthy separate investigation. For example, the EM nature of information flow in such structures has the property of reciprocity, i.e. the ‘execution runs’ in these processes can be played back to the original states, and hence the modelling Petri nets possess a certain notion of reversibility. In his PhD study, Alex Ventisei, is planning to advance this modelling work further to capture more complex structures of TEM pulse interactions, and complement the existing methods of modelling based on scattering matrices with graphical models using such Petri nets, as well as develop some simulation and analysis tools.
To my previous blog, proving that EM power can only exist in motion with a speed of light, one might react with a question: What about Static EM fields?
(cf. the Static Fields rubric on the wiki page about Poynting Vector: https://en.wikipedia.org/wiki/Poynting_vector)
The corollary of the proposition proven earlier is that there is NO static fields per se.
Of course we need to say what we mean by ‘static’ here. Well static means – Not moving! A common online English dictionary defines static (adjective) as follows: lacking in movement, action, or change, especially in an undesirable or uninteresting way.
So, I then have the full right to surmise that Static fields do not move with speed of light according to this definition. So, there is a contradiction with the proof. Therefore, the only way to resolve it is to conclude that Static Fields DO NOT have the right to exist!
Indeed, what is believed to be static is actually a superposition or contrapuntal effect of normally moving fields (Poynting vectors to be precise), where their stepping or pulsing effects are not visible. A normal illusion due to superposition.
One might ask but what about for example a cylindrical capacitor shown on //en.wikipedia.org/wiki/Poynting_vector ?
The answer is that – just the same thing – the are at least two power flows of ExH form there – like two conveyor belts of sheaths moving against one another, where the H (magnetic components are superposed and show the cumulative effect of H=0). Just short-circuit this cylinder from at least one edge, and you will see the effect of transition (redistribution) of the magnitudes of E and H so that the total amount of power ExH crossing the spatial cross-section will remain the same.
So Static Field (as being static in the sense of the above definition) is an illusion – just another H G Wells’ Invisible Man visiting us!
On the Necessity and Sufficiency of Poynting vector’s motion with speed of light for the existence of contrapuntal states observed in Wakefield experiments
(see my earlier post: https://blogs.ncl.ac.uk/alexyakovlev/2019/09/14/wakefield-4-experiment-causal-picture-in-energy-current/ and Ivor Catt’s original paper on Wakefield 1: http://www.ivorcatt.co.uk/x343.pdf)
Alex Yakovlev
13 August 2020
The main hypothesis is:
H: EM energy current in the form of ExH (aka Poynting vector) can only exist in motion with a speed of light.
Experiment:
Consider a Wakefield experiment with a Tx Line that is initially discharged.
At time t=0, the TL is connected at point A (left-hand side) to a source 10V, where it is terminated with an open circuit. Point B is in the middle. Point C is at the right-hand side and is short-circuited.
Wakefield shows that:
At point A we have a square shape oscillation between +10V (half-time) and -10V (half-time).
At point C we see no changes – completely discharged line at 0V.
At point B we have the following cyclically repeated sequence of phases: (a) 0V (quarter time), (b) +10 (quarter time), (c) 0V (quarter time), (d) -10V (quarter time).
A similar analysis can be carried out with an initially charged TL which is short-circuited at point A and is open-circuited at point C.
Experimental fact:
W: We observe contrapuntal effects in Wakefield, such as in Point B we have phases (a) and (c) where the cumulative effect of ExH field waves makes them look observationally equivalent – at 0V, yet leading to different subsequent behaviour, i.e. from (a) it goes to (b), and from (c) it goes to (d).
The proposition:
P: The contrapuntal effects that we observe in Wakefield hold if and only if ExH can only exist in motion with a speed of light.
In other words, we state that W is true if and only if H holds, i.e. H is a necessary and sufficient condition for W.
Proof:
Sufficiency (H->W):
Suppose H is true. We can then easily deduce that at every point in space A, B and C, the the observed waveform will be as demonstrated by Wakefield.
(Ivor’s website contains my prediction for Wakefield 3 with contrapuntal behaviour – the analysis was based on Ivor’s theory – i.e. hypothesis H, and it was correctly confirmed by the experiment. For details see: http://www.ivorcatt.co.uk/x91cw34.htm and http://www.ivorcatt.co.uk/x842short.pdf)
Necessity (W->H, which is equivalent to not H -> not W):
Suppose H does not hold, i.e. at some point in space and/or in time, ExH is stationary or does not travel with speed of light. Let’s first look, say at point C. We see a “discharged state” – it corresponds to what we may call stationary state electric field, i.e. E=0 – a discharged piece of TL. Here we can possibly say that the voltage across it is constantly equal to 0 because at C it is short-circuited.
Next, we look at point B at the time when the voltage level is equal to 0V, say in phase (c). We think it is a static E=0. Using the same argument as we did for point C. One might argue that the point B is not short-circuited, but this does not matter from the point of view of our observation – it’s just 0V.
How can we predict that after a specific and well-defined time interval, voltage at B will go down to -10V and not up to +10V as it would have gone had we been in phase (a)? In other words, how can we distinguish the states in those two phases using classical theory, where phase (a) is observationally equivalent to phase (c).
The only way we could predict the real behaviour in W with classical theory if we had some ADDITIONAL memory that would store information, in another object, that although we were stationary here in that place and time interval, we were actually being in transit between phases (b) and (d) rather than being in transit between (d) and (b).
The fact that we need ADDITIONAL memory (another TL) is something that is outside the scope of our original model, because we did not have it organised in the first place. So, there is no knowledge in the original model that will make us certain that from phase (c) we will eventually and deterministically go to phase (d).
Q.E.D.
Note: The above fact of having phases (a), (b), (c) and (d) is the result of the contrapuntal effect of the superposition of the partial actions performed by the steps moving in the right and left directions. And unless that motion was always (in time and in space) with a well-defined speed (speed of light), we would not be able to predict that from phase (c) we will definitely and only transition to phase (d) and not to phase (b) and how quickly that transition will happen. The case of a fully charged or fully discharged capacitor, with seemingly stationary E field, that is a contrapuntal effect of superposed motion of ExH in all directions, is just a special case of the TL.
Remark from David Walton:
The only way we could predict the real behaviour in W with classical theory if we had some ADDITIONAL memory that would store information, in another object, that although we were stationary here in that place and time interval, we were actually being in transit between phases (b) and (d) rather than being in transit between (d) and (b).
is the key point.
Another way to state the same thing in different context and less formally (I think) is to point out that when two pulses travelling in opposite directions pass through each other either the B or E fields will cancel, hence demonstrating that the field cannot be the cause of the onward propagation of the em pulse.
My response:
That’s a great point you make. Indeed the absence of either B or E in the contrapuntal state disables us from the ability to talk about further propagation of the pulses.
Yes, the key point is the absence of memory about the dynamical process in the classical field model.
In summary:
Illusions … How many we have every day because we don’t really know they are happening around us (not enough sensors or memory to track things).
The contrapuntal effects are those that H G Wells probably had in mind in the shape of the Invisible Man. They blind us from reality …
In my email exchange with Ivor Catt, a following idea came to my mind.
The law of energy conservation as it is being presented to students and understood is rather abstract as it begs for many interpretations, because energy exists in its permanent and omnipresent motion. Even if it is trapped in a fragment of space like a capacitor or an elementary particle it is in motion.
So, what seems to be less convoluted is the law that energy can only exist in motion and it can only move at speed of light. That’s actually what conservation of energy is. This is true by Occam’s razor principle and does not need to be proven. So, it is necessarily so before or after the switch [between voltage source and a capacitor] is closed … and without this law we would not have had those prefect contrapuntal effects, including those that ’cause’ people to think we have stationary conditions in capacitors and transmission lines.
There is a constant debate in Electromagnetism between the Charge-based views and Field-based views. I am of course over-simplifying the picture here, at least terminologically. But the main point is that you can talk about EM either from the point of view of; (i) objects that have mass, like electrons, protons, ions etc – I called them collectively charges or charge carriers, or (ii) entities that carry EM energy, like strength of electric and magnetic field, Poyinting vector etc – those are not associated with mass. Both views are often linked to some form of motion, or dynamics. For the world of objects people talk about moving charges, electric current, static charges etc. For the world of fields, people talk about EM waves, TE, TM and TEM, energy current, static field etc.
Often people talk about a mix of both views, and that’s where many paradoxes and contradictions happen. For example, there is an interesting ‘puzzle’ that has been posed to the world by Ivor Catt. It is sometimes called Catt’s question or Catt Anomaly.
http://www.electromagnetism.demon.co.uk/cattq.htm
Basically, the question is about: when a step in voltage is transmitted in a transmission line from a source to the end, according to the classical EM theory charge appears on both wires (+ on the leading wire, and – on the grounded wire): Where does this new charge come from?
Surprisingly, there has not been a convincing answer from anyone that would not violate one or another aspect of the classical EM theory.
Similar to this, there is a challenge posed by Malcolm Davidson, called Heaviside Challenge https://www.oliver-heaviside.com/ that hasn’t also been given a consistent response even though the challenge has been posed with a 5 thousand USD prize!
So it seems that there is a fundamental problem in reconciling the two worlds, in a consistent theory based on physical principles and laws, rather than mathematical abstractions.
However, there is a hope that with the way to understand and explain EM phenomena, especially in high-speed electronic circuits, is through the notion of a Heaviside signal and the principle of energy-current (Poyinting vector) that never ceases from travelling with the speed of light in the medium. In terms of energy current perfect dielectrics are perfect conductors of energy, whereas perfect charge conductors are perfect insulators for EM energy current.
So, while those who prefer the charge based view of the world may continue to talk about static and dynamic charges, those who see the world via energy current live in the world where there is no such a thing as static electric or magnetic field, because TEM signal can only exist in motion with a speed of light in the medium. Medium is characterised by its permittivity and permissibility and gives rise to two principal parameters – speed of light and characteristic impedance. The inherent necessity of the TEM signal to move is stipulated by Galileo/Newton’s principles of geometric proportionality, which effectively define the relations between any change of the field parameter in time with its change in space. Those two changes are linked fundamentally, hence we have the coefficient of proportionality delta_x/delta_t, also known as speed of light, which gives rise to causality between the propagation of energy or information and momenta of force acting on objects with mass.
Another consequence of the ever-moving energy current is its ability to be trapped in a segment of space, pretty much what we can have in a so called capacitor, and thus form an energized fragment of space, that gives rise to an object with mass, e.g. a charged particle such as an electron. So, this corollary of the first principle of energy current paves the way to the view of EM that is based on charged particles.
The current fight of the human race against the deadly coronavirus shows the obvious inability of a capitalist, free-market system to handle it.
Nations with more centralised economy and command-control mechanisms already in place are better equipped with tools to respond and act.
Many businesses in all industries close to our daily life are at standstill, and sadly may never recover from this plight or it might take a long time if things get back to normal. It is obvious that prolonging capitalism and its functionalities, and not rapidly changing the course to socialism would lead to great human losses and disasters. The nation will suffer at all levels of its structure enormously if the crisis extends for months.
What then to do? How to re-act?
It is worth looking at the history of societies and nations which underwent economic and political cataclysms and see what was done there and at what cost, and what perhaps could have been done differently.
Take Soviet Union after the October revolution for example. A switch to socialism was very painful, it was not done smartly and systematically but as a result of a bloody and brutal overthrow of the previous system, but there were certain moments when a clever action of the leadership helped to mitigate the tragedy. For example, switching to the so called “Military Communism” was essential during that plight. One thing should be clear is that the leaders should be smart enough and steer the nation quickly towards socialist realities.
Instead of trying to pay a significant salary replacement to workers who are now effectively unemployed (the bureaucracy of this process will not be sustainable in these speedy dire straights of the pandemic), we need to face the reality and give people the absolute basics. People should be given some comfort of hope in material sense – guaranteed food, shelter, moral and medical support. If someone rents a place to live and has no cash to pay the rent now, the government should, perhaps in a very crude and direct way, issue a decree that the owners shall NOT demand rent from people who lost their job. Small elements of “temporary expropriation” (I am not calling to the disownership of the property!) are needed. The fate of the nation is at stake. And the nation is its people.
Clearly, a government that was brought up on the principles of free economy, conservatism and capitalist values, would have enormous problems to simply turn the switch from capitalism to socialism. But what can we do? We have to live with the government that was elected by the people. And it happens to be conservative. So be it. Thus, we can only hope in some remains of common sense in this government and we can only try to impact on their policies to be more decisive. They should realise that the country urgently needs to switch to some forms of socialism and more direct rule.