Implementing a Neuron in Analog Circuit

The fundamental unit of computation in a neural network is a perceptron or a logistic unit. Over past couple of months, I have been looking at analog implementation of perceptron.  Here is a simple architecture for it:

Image result for perceptron

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The above architecture can be implemented in an analog circuit using OpAmps as shown below:

Here, First OpAmp is implementing a summer. The output of it is given as:

Vs = – { (RF/R0) x 1 + (RF/R1) x X1 + (RF/R2) x X2 + (RF/R3) x X3 + (RF/R4) x X4 }

As one can see, weights w0 = (RF/R0), w1 = (RF/R1), w2 = (RF/ R2) …

V0 is a thresholding of Vs with a very low threshold by employing an inverting schmitt trigger.

By employing memristors in place of R0, R1, R2, R3 and R4. This can be made a trainable logistic unit. Connecting many such units we can make a neural network in analog. The advantage of such neurons are their speed and parallelism. They can operate even when inputs are available only partially.

Tyranny of the new Motor Vehicles Act

The new Motor vehicle (MVA) act enacted from September 1 is one of the most tyrannical laws implemented in India. Its hall mark is its outrageous penalties that are unmatched even in the most advanced countries in the world with excellent traffic rule compliance.

Average traffic fines in USA are around $150 while the average income in USA is about $2700 per month. This makes the Fine to Income ratio about 5 percent in USA. The new MVA has raised the average penalties above Rs. 2000/-. Per capita income of Indians is about Rs. 10000/- per month.  So the fine to income ratio is about  20 percent in India.

Even after public outcry about such outrageous penalties, central government with a brute majority in parliament seems to be failing to respond on this matter. With a slumping growth rate, if the government thinks that it can garner more money by looting public through such tyrannical rules, I am afraid this has never succeed in history anywhere. Increased taxation and penalties lead to squeeze in economy. In this case, lesser vehicles on road and lesser sales of fuel will lead to even further slowdown in the economy. The public fights between police and citizens is visible across TV screens on daily basis.  Roads are appearing like battlefields. Such tensions between law enforcement and citizens will lead to social dissensions and further loss of faith in the system. Apart from this, such high penalties will promote bribery and corrupt arrangements between traffic police and citizens.

Sane rule of jurisprudence says that the punishment should be proportionate to the offence. Increasing penalties do work, but to what extent? Has the government thought of the rationale behind this? Why not give capital punishment for driving without licence? That might work even better!

Punishing the citizens is Okay but what about the punishment for the government? Where is the punishment for bad roads? Where is the punishment for children falling into manholes? No street lights? Why should only citizens be punished!

Einstein discovered gravity!

Our Railway minister Piyush Goyal said today that Einstein discovered gravity. I am not too concerned about this gaffe which might have been an unintentional slip of the tongue. But what concerns me as a citizen with a scientific mind is his comment that maths have never helped Einstein discover gravity and a general alluring to the idea that maths is non-essential in prediction of future course of economy.

This is the classic anti-intellectual sentiment created by politicians in face of sane criticism that, raw emotional decisions are better than well thought out plan by thinkers. He emphasized that even if economy is growing at 5%, we are well on our way to achieve $5 trillion economy by 2024. Size of current Indian economy is $2.5 trillion. So, we would need about 15% growth rate to double our economy in 5 years. Even a common man knows that doubling your money in 5 years would need a compound interest of 15% per annum.

And yes, about Einstein, gravity and maths, anyone with a high school education knows that without maths, analysis of neither gravity nor relativity is possible. Unfortunately, maths, correctness of data recording and taking help from well established economists do not appear to be a strong point of this government.