Berbicara tentang Agent
March 18, 2012
- Agent – Anything that perceives its environment through sensors and acts upon that environment through actuators.
- Percept – An agent’s perceptual inputs at a given instant.
- Percept sequence – Complete history of percepts.
- Performance measure, embodies the criterion for success of an agent’s actions.
- Fully/partially observable – fully observable if can sense entire environment.
- Deterministic/stochastic (nondeterministic) – deterministic if next state completely determined by current state and agent action; otherwise stochastic.
- Episodic/sequential – episodic if next episode does not depend on previous episodes; sequential if current decision can affect future decisions.
- Static/dynamic – dynamic if environment can change after agent senses but before agent acts.
- Discrete/continuous – how time is handled; how environment changes over time and agent percepts and actions. If time is not a factor then discrete.
- Single/multi agent – multi-agents may compete or cooperate (e.g. two agents playing chess or a pilot and flight controller agent flying airplane).
Agents and Environments
- Agents include humans, robots, softbots, thermostats, …
- Agent function f maps from percept histories P to actions A:f : P* g A
- Agent program runs on the physical architecture of a computer to perform f
- Percepts: location and status, e.g. [A, Dirty]
- Actions: Left, Right, Suck, NoOp
The Structures of Agents
Four basic types in order of increasing generality:
- simple reflex agents – select action based on current percept, ignoring percept history.
- reflex agents with state – select action based on percept history
- goal-based agents – select action to achieve some goal
- utility-based agents – select action that achieves best measure of succes
All above can also be learning agents that analyze experience to select action.
- Program = algorithm + data
- Agent program implements agent function mapping percepts to actions: f : P* g A
- Architecture is the computing device with sensors and actuators
- Agent = architecture + program