Thursday, May 2, 2019


How Predictable is the Future of Solar Energy?

Reference: JD Farmer and F Lafond, How predictable is technological progress? Research Policy, 45(2016):647-665, www.sciencedirect.com/science/article/pii/S0048733315001699


                       Farmer and Lafond's Figure 1. 

Is solar exponential? Nuclear? Coal?

Problem: Why Moore's law?


Answer (partial at least):

Next year's value is often this year's value + a percentage

Why?









Analogy: what is the rate of water evaporation?

But the percentage increase is very noisy
  • Dr. S invents a new advance
  • Recession holds back progress
  • Companies merge/go out of business
  • Government policies do whatever
  • Etc.

How to model that along with %/year increases?
  • Geometric random walk
    • This captures:
      • The trend (geometric - discretely exponential)
      • The noise (random walk)
  • Add in autocorrelation
    • Models that the noise changes slowly

We can now figure:

      the distribution of possibilities at a given future time

  • See Farmer and Lafond, equations (1) through (16)! ☺️


                   Farmer and Lafond's Fig. 10. 

What is the probability of being below the dashed line?

What is the probability of prices stalling until at least 2028?
Image result for how much is a standard deviation?

Remember the Cone of Uncertainty concept?



Farmer and Lafond's Fig. 11: 
"Probability that solar photovoltaic modules become less expensive than a hypothetical competing technology C whose initial cost is one third that of solar but is on average not improving..."


Cognitive Enhancement

Drugs that enhance normal mental functioning are possible


Stimulants often improve performance

You can call it "doping"

Just like in sports

Maybe we wish it weren't so!




Substance, etc.
Main action
Mediating mechanism
Nicotine
Increase concentration (etc.)
Increase acetylcholine (etc.)
Strychnine
Stimulant
Block glycine receptors
Caffeine
Stimulant
Decrease tiredness
Hydromel (unfermented)*
Increase available energy
Raise blood sugar
Sage
Improve memory
Inhibit cholinesterases
Chewing gum
Improve memory
Uncertain
Modafinil (Alertec, Provigil)
Maintain alertness
Anti-sleepiness
Alcohol
Enhance creativity
Improve incubation phase
Methylphenidate (Ritalin)
Improve focus
Stimulate central nervous system
Amphetamines
(Adderall)
Improve focus
Stimulate central nervous system
Piracetam
Enhance cognition
Increase brain metabolism
Hydergine (ergoloid mesylates)
Enhance cognition
Increase brain metabolism
Donepizil (Aricept)
Improve memory
Inhibit cholinesterases
Cortactin
Enable neural plasticity
Circumvent calcain biomolecules
Magnesium threonate
Enhance learning & memory
Increase synapse plasticity
Insulin-like growth factor 2
Improve memory
Enhance memory consolidation
Metformin
Improve learning
Stimulate neurogenesis
Exercise
Enhance cognition
Stimulate neurogenesis
Afternoon napping
Improve learning
Clear hippocampal input queue
NgR1 antagonist
Enhance neural plasticity
Reduce demyelination; increase synapse turnover
Fish, except fried
Uncertain
Increase brain tissue volume
Klotho
Enhance cognition
Side effect of life extension
GLYX-13
Improve memory
Acts on brain’s hippocampus



Table 1. Some cognitive enhancement substances and activities. (Not recommended for use nonmedical use)

There are basically only a few strategies for cognitive enhancement

  • Stimulation. 
    • Coffee or any other stimulant makes the brain, or parts of the brain, work harder.
  • Neuroplasticity. 
    • Learning requires updating the neural connections, so ways of making these connections change faster can speed learning.
  • Augmentation. 
    • Brain augmentations could work via anything from chips inserted in the brain to hats with embedded electrodes.
  • Bootstrapping. 
    • If you learn something, then you are smarter. Called “education,” this is not the “easy way” to enhanced cognition — but in the long run may be the most effective.
  • Health care. 
    • Innumerable health related issues, mental and physical, can reduce cognitive performance. Fixing them will thus improve cognition.
Let’s look at some examples next.

Transcranial Electrical Stimulation (TES)

  • Pills take at least a few minutes
  • Raw electricity...
  • Fast. The call it "juice" for a reason
  • Electricity applied directly to the head
  • Typically 1-2 mA
  • Electroshock therapy: around 800 mA
  • In 1883,5 Sylvanus Thompson described connecting a battery to the forehead to cause a “wild rush of colour” 
  • He did not claim to have tried it himself
    • but he didn't say he didn't


Numerous studies have shown TES to be able to improve performance in normal people on a wide variety of cognitive tasks related to language, arithmetic, learning, skill acquisition, and planning. 

You can get TES devices commercially with a doctor’s prescription. 

You can even build your own TES machine on the cheap from do-it-yourself plans.


DBS:

For more focused application, insert electrodes into brain

Promising results for:

Depression

Parkinson's disease

Obsessive-compulsive disorder

Using it instead for brain enhancement: a no-brainer?

2011: found to make mice smarter

So why not rats?

So why not humans in the rat race of life?


TMS
transcranial magnetic stimulation

No need for pesky wires in the skull!

An approved treatment for depression

Can lead to hypomania

Is that a problem?

People with hypomania are energetic and elated, which can be a kind of cognitive enhancement.


Ultrasound
Another method uses ultrasound, or sound waves above the audible range of frequencies.

Visual hemispheric invocation (VHI)

To invoke the right hemisphere, simply focus your eyes on a point, while focusing your attention on something to the right of that point in the peripheral visual field. 

           
A better method?

A tried-and-true method for cognitive enhancement is to associate with others with whom you have similar goals and interests. Sometimes called the “critical mass” effect, anyone who has been in such a group can vouch for its effectiveness.23