Third edition of Artificial Intelligence: foundations of computational agents, Cambridge University Press, 2023 is now available (including the full text).
1.5.4.1 Sensing Uncertainty
In some cases, an agent can observe the state of the world directly. For example, in some board games or on a factory floor, an agent may know exactly the state of the world. In many other cases, it may only have some noisy perception of the state and the best it can do is to have a probability distribution over the set of possible states based on what it perceives. For example, given a patient's symptoms, a medical doctor may not actually know which disease a patient may have and may have only a probability distribution over the diseases the patient may have.
The sensing uncertainty dimension concerns whether the agent can determine the state from the observations:
- Fully observable is when the agent knows the state of the world from the observations.
- Partially observable is when the agent does not directly observe the state of the world. This occurs when many possible states can result in the same observations or when observations are noisy.
Assuming the world is fully observable is often done as a simplifying assumption to keep reasoning tractable.
