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AI23 Assignment 2
BEAST Simulation Modelling

Due date: 21 April, 2008, 5pm

1. Braitenberg vehicles in BEAST

(a) Run the Braitenberg demo. Describe the behaviour of the two vehicles. (Try positioning them at various places in the model world & describe how they "react".)
(b) How do the vehicles use sensory information to control the orientation and velocities? What file did you have to look at to find the answer?
(c) What specific control laws govern the motor behaviour of each vehicle? What change could you make in the code to test your conclusion?
(d) Can you ascribe any intelligence to the vehicles? Explain and argue your case.

2. Mouse demo in BEAST

(a) Run the mouse demo. Describe the evolution of the behaviour of the mice. (How do they behave initially, as evolution progresses, and after a long evolutionary time?) Provide supporting evidence.
(b) What collective behaviour is observed, if any? Give supporting evidence. Explain why collective behaviour is possible/impossible in this demo.
(c) Describe the fitness or performance of the mice over the generations. Do the mice progressively improve? Do they reach a stable evolutionary solution, and if so what is it? Furthermore, how do fitness values of the population and the individuals in it evolve over time? Explain and provide supporting evidence for your answers.
(d) What is the fitness function used in this GA? Find it in the code and justify it. Does this fitness function produce an "optimal" strategy for these mice? Explain.
Recommendation: In order to help you answer this question, try to think of other formulations of the fitness function, edit the code and try them out; compare your findings with the original and modified fitness functions. Can you explain the discrepancies you found (if any)?
(e) What modifications would you incorporate in this code (in the neural network, sensors, fitness function or combination thereof) to improve the performance of these mice? Be as specific as possible in the suggestions you make and justify your answer.
(f) Implement your solution and test it.

Getting Started:

(a) See this link for BEAST installation details and instructions.
(b) BEAST documentation is found here
(c) A brief User's Guide can be found here
Instructions:

(a) For question 2 all coding or code modifications can be done within the project example file (mouse.cc in the BEAST/examples/ directory).
(b) Files must be compilable with the command "make filename" (e.g., make mouse).
(c) Random number seeds must be hard coded into the program file and specified in the solutions.
(d) You are encouraged to consult with your fellow students. However, all work you submit must be your own.

Deliverables: Please follow these instructions carefully:
Your coursework should be submitted electronically via SIS. Your submission should contain two files:
Answers to questions should be submitted in one of the following formats:
a PDF document entitled cw2.pdf
a Word document entitled cw2.doc
an OpenOffice document entitled cw2.doc
All codes and related (make, pop) files should be included as a single tar archive entitled 'mouse.tar'. The archive should include:
(i) Working code entitled 'mouse.cc' and any additional versions of your codes entitled 'mouse_v?.cc' where '?' is replaced by a digit (e.g., mouse_v1.cc, mouse_v2.cc, etc.). Note than both asnwers to questions and comments in the codes must clearly indicate which code (or code fragment) should be associated with which question (or subquestion) for marking.
(ii) Simulation solutions (relevant .pop files) may also be submitted.
(iii) Make files as necessary.
Please DO NOT submit executables.

Marking: This assignment is worth 25% of the final grade. Questions are not marked uniformly, but according to the following scheme:
Q1 : 20 points (a 4; b 4; c 4; d 8);
Q2 : 80 points (a 8; b 8; c 8; d 12; e 20; f 24);
Total : 100 points.

Good luck!

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