LECTURE 4: PRACTICAL REASONING 1 Practical ... - Sorry

Lecture 4
An Introduction to Multiagent Systems
Lecture 4
An Introduction to Multiagent Systems
Agent Control Loop Version 6
1.
2. BB¼;
3. II¼;
4. while true do
5. get next percept;
6. Bbrf´Bµ;
7. Doptions´BIµ;
8. Ifilter´BDIµ;
9. plan´BIµ;
10. while not (empty´µ
or succeeded´IBµ
or impossible´IBµ) do
11. «hd´µ;
12. execute´«µ;
13. tail´µ;
14. get next percept;
15. Bbrf´Bµ;
16. Doptions´BIµ;
17. Ifilter´BDIµ;
18. if not sound´IBµthen
19. plan´BIµ
20. end-if
21. end-while
22. end-while
¯But intention reconsideration is costly!
A dilemma:
– an agent that does not stop to reconsider its intentions
sufficiently often will continue attempting to achieve its
intentions even after it is clear that they cannot be achieved,
or that there is no longer any reason for achieving them;
– an agent that constantly reconsiders its attentions may spend
insufficient time actually working to achieve them, and hence
runs the risk of never actually achieving them.
¯Solution: incorporate an explicit meta-level control component,
that decides whether or not to reconsider.
http://www.csc.liv.ac.uk/˜mjw/pubs/imas/ 36
http://www.csc.liv.ac.uk/˜mjw/pubs/imas/ 37
Lecture 4
An Introduction to Multiagent Systems
Lecture 4
An Introduction to Multiagent Systems
Agent Control Loop Version 7
1.
2. BB¼;
3. II¼;
4. while true do
5. get next percept;
6. Bbrf´Bµ;
7. Doptions´BIµ;
8. Ifilter´BDIµ;
9. plan´BIµ;
10. while not (empty´µ
or succeeded´IBµ
or impossible´IBµ) do
11. «hd´µ;
12. execute´«µ;
13. tail´µ;
14. get next percept;
15. Bbrf´Bµ;
16. if reconsider´IBµthen
17. Doptions´BIµ;
18. Ifilter´BDIµ;
19. end-if
20. if not sound´IBµthen
21. plan´BIµ
22. end-if
23. end-while
24. end-while
¯The possible interactions between meta-level control and
deliberation are:
Situation Chose to Changed Would have reconsider´µ
number deliberate? intentions? changed intentions? optimal?
1 No — No Yes
2 No — Yes No
3 Yes No — No
4 Yes Yes — Yes
http://www.csc.liv.ac.uk/˜mjw/pubs/imas/ 38
http://www.csc.liv.ac.uk/˜mjw/pubs/imas/ 39