Copy of 4.Utility based agent PDF

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Utility based agent details,how it works with example.Explained in a very easy way so that everyone could understand easily....

Description

UTILITY BASED AGENT What is a Utility based agent ? A utility-based agent is an agent that acts based not only on what the goal is, but the best way to reach that goal. In short, it is the usefulness or utility of the agent that makes itself distinct from its counterparts.

Goals are qualitative: A goal specifies a crude distinction between a happy and unhappy state, but often needs a more general performance measure that describes “degree of happiness.” Let’s say, you are going on a tour with your friends by bus. You will reach the destination but you’ll want to enjoy the journey and this will remain as a good memory for the rest of your life. So, here this enjoyment/utility is your focus and you are acting like a utility based agent here.

? when we have to chose UBA and in which scenario ? which agen reacts very fast Utility Function – Utility function U: State → R indicating a measure of success or happiness when at a given state.

Important for making tradeoffs: Allows decisions comparing choice between conflicting goals, and choice between likelihood of success and importance of goal (if achievement is uncertain). ? Difference between SRA And UBA ? In which situation GBA is better than UBA ? Briefly explain its implementation in an abstract way

What is considered by a Utility based agent ? Goals are not always enough – Many action sequences get taxi to destination – Consider other things. How fast, how safe or happy state. Focus on utility not goal. Obviously, we need to reach a goal, but here it keeps the goal in minds but focus is on utility. Means, my actions lead the agent to which state? happy or sad. State’s happiness or unhappiness measured by this agent.

Pseudocode – function UTILITY-BASED-AGENT(percept) returns an action. persistent: state, the agent’s current conception of the world state goal, a description of what the agent would like to achieve rules, a set of condition-action rules action, the most recent action.

state ← UPDATE-STATE (state, action, percept, possible states) rule ← RULE-MATCH (state, rules, possible states) action ← rule.ACTION return action [ agent update it’s state to understand how the user is feeling now then match the rule for being in happy state and perform the action.]

? How to Implement UBA ? Explain pseudocode of UBA ? Real life example of UBA ? how it can be implemented

Work Process –

Here, it senses environments฀ save current state ฀ compare it with the past history ฀ keep utility in mind and measures agent is happy or not ฀ actuator performs that action ฀change in environment happens.

Real life application– 1. Real life examples, like GPS system. We set our destination to our goal. It shows more than one path, we are in a happy state. But, maybe there can be traffic jams or there can be protest. state changed now in an unhappy state. Because we can't reach our goal within the time. Here, GPS will show another path or shortcut. so, again we'll be in a happy state. Utility function measures happy or unhappy state. It works in a partially observable environment. Cause, I know my car features. Don’t know about other cars or roads. 2. Another example, let’s show our mars Lander on the surface of mars with an obstacle in its way. In a goal-based agent it is uncertain which

path will be taken by the agent and some are clearly not as efficient as others but in a utility-based agent the best path will have the best output from the utility function and that path will be chosen.

Why a Utility based agent ? Just having goals isn’t good enough because often we may have several actions which all satisfy our goal so we need some way of working out the most efficient one. A utility function maps each state after each action to a real number representing how efficiently each action achieves the goal. This is useful when we either have many actions all solving the same goal or when we have many goals that can be satisfied and we need to choose an action to perform. A utility function maps a state onto a real number which describes the associated degree of “happiness”, “goodness”, “success”.

Advantages – • Selection of best action based only on current state of world and rules • Simple, very efficient • Sometimes robust

Limitations – ● No memory (doesn’t keep track of world) • Limits range of applicability...