Tuesday, January 28, 2014

Process Control Theory simplified

You can read an entire engineering process control book and not get an intuitive feel for what it means.  An introductory book basically covers how to use feedback from the output to adjust an input to control processes to achieve a desired setpoint using a "PID" controller.  For example, a house thermostat is a controller than uses only the "P" element directly by measuring temperature and acting accordingly.  Cruise control and elevators stopping smoothly are other examples.  There is a "hysteresis" (aka "gap") in the on and off actions of a thermostat so that the unit is not cutting on and off all the time too rapidly.   For example if you set it at "70 F" to heat it might turn on at 69 F and turn off at 71 F. This gap is an approximate method of the "I" in the "PID". PID means proportional, integrative, and differential based on the equations that represent the controller.  They can be summed ("wired in parallel") or multiplied but the difference turns out to be semantics in the sense that the multiplier for each (P, I, and D) just changes because the integral of the derivative and the derivative of the integral doesn't really do anything.  The "P" is basically a multiplier that matches the output measurement "voltage" with the input control signal "voltage" (it can be anything besides "voltage" like "force" of an output being matched with "rotation speed" of an input in some pure-mechanical design such as a water-powered mill).  The "I" is a summation of the past outputs (integration) over some time period so it a "memory of the past".  The "D" is the difference over a very brief period of time, the rate at which the output is increasing or decreasing (differential).  So it is a "prediction of the future".  So here's the simplified summary of a PID controller which shows why it's so useful:

P = present
I = past
D = future

Saturday, January 25, 2014

Problems with the Selfish Gene view of evolution

I'm reading "The Selfish Gene" again.  The first 50 if not 100 pages are a nightmare of double-talk and confusion in the author's mind.  This seems to have led to the book's success, irking a lot of people to try to show how it was all wrong-headed.  In his updated version, he cites a few good critiques and explains how he was not so wrong (on the whole) and where he made numerous mistakes in most of the interesting specifics the original book cites, always deferring to his sources as the cause of his errors. His great attribute is in being honest with the details so that a more rational mind can see where his logic fails.  His great error is that he defines "gene" to a sequence of base pairs that is common in nature as a result of 1) long life (the least-important attribute) 2) ability to make many copies 3) that the copies be exact.  In other words, he uses the results of natural selection to define which base pairs are genes, then says the existence of the genes achieve the results we see in nature.  He points out at least twice this is tautological (the definition defines itself) but then tries to give excuses. This is worse than theologians who change the definition of God (their religious writings) to suit new facts coming in. They at least try not to be tautological.   Dawkins' God for life on Earth is the gene.  He constantly uses the colloquial perceptions  of "desires" such as "selfishness" while constantly reminding the reader it is only shorthand for the sake of writing and comprehension convenience and that the reader should always be able to revert this approximate view back to a more fundamental view of genes simply perpetuating themselves. But the "-ing" of perpetuating is the key error. It always reduces to implying genes in and of themselves are a motive force. He constantly implies genes are in some sense a force of nature that determine outcomes, and therefore able to make predictions about what we may see in nature  and "explaining" why we see certain things.  But genes are just the ingredients nature uses. I think it is much better to view nature as the motive force that capitalizes on accidents that subvert the mindless nature of genes, however anyone wants to define certain sequences of base pairs.

Replicators are a pattern of matter that can extract energy from sunlight, temperature differences (from sunlight or radioactivity), or molecular bonds to use outside matter to make copies of themselves while releasing some of the used energy as waste heat, photons, or molecular bonds that are not part of the resulting copy (or imperfect copy) that is able to repeat (or nearly-repeat) the process.  Replicators that are merely software and the environment is existing computer resources, then "matter" in the above is replaced with "bits", which is still matter in some sense because memory states require 2 differing potential energy states significantly above thermal agitation energy level (kT), and potential energy has a mass.  The energy (food) sources have a more ordered arrangement than the results, so life creates real net disorder in atomic patterns.  For example, photon not captured could have stayed in space a very long time. If they reflect off something there is no net change.  If they hit black they increase the temperature of something which is released over a longer time period as lower-energy photons in all directions. Photons hitting plants creates potential energy bonds between atoms, which darkens the universe even more than photons hitting a black object.  If animals come along and use the energy, some of the potential energy is released as photons or heat (and therefore eventually photons).   But animals might build replicating solar and nanotube structures to capture even more photons and convert them into even higher potential energy structures (strong carbon and silicon bonds that will last a long time), so that the future is even more darkness created by replicating structures.  Sagan in "Cosmic Connection" mentioned Freemon Dyson talking about a spherical shell of solar cells created from the mass of the planets to use all light coming from stars. Sagan dismisses the potential of this causing a star to go dark to the external universe because it would simply heat up to the same temperature, but this assumes higher and higher potential energy bonds are not being created such as more and more strong bonds or converting Sunlight back into protons, neutrons, and electrons that have zero motion relative to each other (no heat).

Hunting and harvesting as related to muscle and memory building.

Eating after heavy exercise builds muscle instead of fat, supposedly because hunting animals leads to more muscles and less fat.  Conversely, eating harvested foods after mild activity would lead to more fat storage and less calorie-burning muscle in order to prepare for winter cold....assuming the genes are from cold places instead of the tropics.  Maybe there is a timing method for when the best rational thinking occurs (like before and during a hunt and you're starving and therefore coconut-oil-like glycogen is in the brain) and when short term memory is translated into long term memory (like after a big meal, if you sit around and think about how the hunt succeeded).  A failed hunt however, would have a crucial and depressing moment when you realized you failed, so that temporary pain could enhance memory.  That evening would not be just remembering the failure, but using glycogen and pain to plan for tomorrow.  In terms of a dementia patient, this would mean have them in a state of hunger before trying to get them to go anywhere or do anything, and then talk to them after a meal about the day's events and anything you want them to remember, but centered on positive and fun thoughts since enhancing the memory of trauma leads to extending the depression and stress.  So think and do stressful stuff when hungry, but be happy and relaxed and thinking about things that need to be remembered when satiated.