Week 4 - Semantics and Ant Colony Optimisation Flashcards
What are the semantics of a program?
All input-output pairs defining the computed function.
What does semantic mutation mean?
Offspring semantically similar to parents.
What does semantic crossover mean?
Offspring semantically intermediate to parents.
What do semantic operators do?
They act on the syntax but guarantee that some semantic criterion (semantic mutation and semantic crossover) hold.
In semantic programming, how is the fitness of a program determined?
By its semantic distance to the optimum.
What is the fitness landscape for semantic geometric genetic programs?
A cone landscape.
What is the emergent property of a swarm?
The ability to do a task X with high probability as a swarm.
Define stigmergy.
Indirect communication via interaction with the environment.
What are the two types of stigmergy?
Sematonic (action of agent directly related to problem solving and affects behaviour of other agents).
Sign-based (action of agent affects environment not directly related to problem solving activity.
What do ants communicate using?
Pheromones.
How do pheromone trails work?
Individual ants lay pheromone trails while travelling from the nest to the nest or possibly in both directions.
The pheromone trail gradually evaporates over time.
But pheromone trail strength accumulates with multiple ants using the path.
Ants prefer paths with more pheromone on them.
