Natural Computation and Self-Organization:
The Physics of Information Processing in Complex Systems

Jim Crutchfield
chaos@cse.ucdavis.edu; http://cse.ucdavis.edu/~chaos

Winter 2008
WWW: http://cse.ucdavis.edu/~chaos/courses/ncaso/

Homework 5

Covering Lecture Notes and EIT Second Edition, Chapters 1 and 2.

  1. Write up your Project Proposal with the following sections. The result should be 1-2 pages long.
    1. Goal: What you would like to learn?
    2. System: Describe how the dynamical system is nonlinear and time-dependent. What’s the state space? What’s the dynamic? Why is it interesting?
    3. Properties: What properties are you going to investigate?
    4. Methods: What methods will you use? Why are they appropriate?
    5. Hypothesis: What is your current guess as to what you will find?
    6. Steps: List the appropriate steps for your investigation; for example, read literature, write simulator, do mathematical analysis, estimate properties from simulation, write up report, and so on.
    7. Time: Estimate how long each step will take. Can you complete the project within one month?
  2. Consider the map of the interval given by
                  (
              |{1 - 2xn  0 ≤ xn ≤ 13
xn+1 = f (xn) = 2xn - 13  13 < xn ≤ 23   xn ∈ [0,1] .
              |(3 - 3xn  2 < xn ≤ 1
                        3
    (1)

    Construct a Markov partition for this map, as follows.

    1. Plot xn+1 versus xn.
    2. Find the monotone pieces of f(x) by determining the locations of its extrema.
    3. Show that the segments defined by the ends of the interval and these locations form a Markov partition.
    4. Give the Markov chain induced by this partition.
    5. Calculate pV () for the Markov chain.
    3. Last week you constructed a 3 element Markov partition PMarkov for the logistic map at the parameter setting where 2 bands merge into 1 band. Analyze a generating partition for this same situation, as follows.
    1. Consider the binary partition of the interval Pgen = {0 ~ (0,1
2),1 ~ (1
2,1)}. Label the transitions in last week’s Markov chain with the symbols observed using Pgen when making transitions between Markov partition elements.
    2. Show that the resulting representation is a deterministic hidden Markov process.
    3. How many internal (Markov) state sequences map onto the observed sequence of all 1s? Are there any other examples of many-to-one mappings of state sequences onto observed sequences?
    4. States are equivalent if the sets of sequences that follow from them are the same. Give a hidden Markov chain with fewer states than the one just constructed by identifying states that are equivalent in this sense.
    4. For the logistic map at r = 4, what sets of initial conditions lead to the sequences s3 = 001 and s3 = 111 when the map iterates are observed with the partition Pgen = {0 ~ (0,1
2),1 ~ (1
2,1)}?
    5. EIT Problem 2.6. (EIT 1st edition: was Problem 2.10.)
    6. EIT Problem 2.12. (EIT 1st edition: was Problem 2.16.)
    7. EIT Problem 2.15. (EIT 1st edition: was Problem 2.21.)

    Homework due one week after being assigned.