Autonomous Agents and Multi-Agent Systems

, Volume 28, Issue 4, pp 682–719 | Cite as

An operational semantics for the goal life-cycle in BDI agents

  • James Harland
  • David N. Morley
  • John Thangarajah
  • Neil Yorke-SmithEmail author


A fundamental feature of intelligent agents is their ability to deliberate over their goals. Operating in an environment that may change in unpredictable ways, an agent needs to regularly evaluate whether its current set of goals is the most appropriate set to pursue. The management of goals is thus a key aspect of an agent’s architecture. Focusing on BDI agents, we consider the various types of goals studied in the literature, including both achievement and maintenance goals. We develop a detailed description of goal states (such as whether goals have been suspended or not), and a comprehensive suite of operations that may be applied to goals (including dropping, aborting, suspending and resuming them). We provide an operational semantics corresponding to this detailed description in an abstract agent language (CAN), and demonstrate on a detailed real-life scenario. The three key contributions of our generic framework for goal states and transitions are (1) to encompass both goals of accomplishment and rich goals of monitoring, (2) to provide the first specification of abort and suspend for all the common goal types, and (3) to account for plan execution as well as the dynamics of subgoaling. Our semantics clarifies how an agent can manage its goals, based on the decisions that it chooses to make, and further provides a foundation for correctness verification of agent behaviour.


BDI agents Goal management Operational semantics 



We are grateful to an anonymous reviewer for this point. We thank Lin Padgham, Sebastian Sardiña, and the participants of the DALT’10 workshop for discussions. We thank the reviewers of the earlier versions of this article for thoughtful and detailed comments which have improved the work. JT acknowledges the support of the Australian Research Council and Agent Oriented Software Pty. Ltd. under Grant LP0453486. NYS acknowledges the support of the University Research Board of the American University of Beirut, and thanks the Operations group at the Judge Business School and the fellowship at St Edmund’s College, Cambridge. The work of DNM and NYS through SRI International was supported in part by the Defense Advanced Research Projects Agency (DARPA) under Contract No. FA8750-07-D-0185/0004. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of DARPA, or the Air Force Research Laboratory.


  1. 1.
    Anderson, C. (1990, August). The first rover on Mars—The Soviets did it in 1971. The Planetary Report.Google Scholar
  2. 2.
    Bajracharya, M., Maimone, M. W., & Helmick, D. (2008). Autonomy for Mars rovers: Past, present, and future. Computer, 41(12), 45–50.CrossRefGoogle Scholar
  3. 3.
    Baral, C., Eiter, T., Bjaereland, M., & Nakamura, M. (2008). Maintenance goals of agents in a dynamic environment. Artificial Intelligence, 172(12–13), 1429–1469.CrossRefzbMATHMathSciNetGoogle Scholar
  4. 4.
    Bordini, R. H., Fisher, M., Visser, W., & Wooldridge, M. (2004). State-space reduction techniques in agent verification. In Proceedings of AAMAS’04 (pp. 896–903), New York.Google Scholar
  5. 5.
    Bordini, R.H., Hübner, J. F. (2010). Semantics for the Jason variant of AgentSpeak (plan failure and some internal actions). In Proceedings of ECAI’10 (pp. 635–640), Lisbon.Google Scholar
  6. 6.
    Braubach, L., & Pokahr, A. (2009). Representing long-term and interest BDI goals. In Proceedings of 7th international workshop on programming multi-agent systems (ProMAS’09), Budapest.Google Scholar
  7. 7.
    Braubach, L., Pokahr, A., Moldt, D., & Lamersdorf, W. (2004). Goal representation for BDI Agent systems. In Proceedings of 2nd international workshop on programming multi-agent systems (ProMAS’04) (pp. 9–20), New York.Google Scholar
  8. 8.
    Burmeister, B., Arnold, M., Copaciu, F., & Rimassa, G. (2008). BDI-agents for agile goal-oriented business processes. In Proceedings of AAMAS’08 (industry track) (pp. 37–44), Estoril.Google Scholar
  9. 9.
    Chopra, A., Dalpiaz, F., Giorgini, P., & Mylopoulos, J. (2010). Modeling and reasoning about service-oriented applications via goals and commitments. In Proceedings of 22nd conference on advanced information systems engineering (CAiSE’10) (pp. 113–128), Hammamet.Google Scholar
  10. 10.
    Cohen, P. R., & Levesque, H. J. (1990). Intention is choice with commitment. Artificial Intelligence, 42, 213–261.CrossRefzbMATHMathSciNetGoogle Scholar
  11. 11.
    da Costa Pereira, C., & Tettamanzi, A. (2010). Belief–goal relationships in possibilistic goal generation. In Proceedings of ECAI’10 (pp. 641–646), Lisbon.Google Scholar
  12. 12.
    Dastani, M., Hindriks, K. V., Meyer, J. J. (Eds.). (2010). Specification and verification of multi-agent systems. New York: Springer.Google Scholar
  13. 13.
    Dastani, M., van Riemsdijk, M. B., & Meyer, J. J. C. (2006). Goal types in agent programming. In Proceedings of AAMAS’06 (pp. 1285–1287), Hakodate.Google Scholar
  14. 14.
    Dastani, M., van Riemsdijk, M. B., & Meyer, J. J. C. (2006). Goal types in agent programming. In Proceedings of ECAI’06 (pp. 220–224), Riva del Garda.Google Scholar
  15. 15.
    Sardiña, S., de Silva, L., & Padgham, L. (2006). Hierarchical planning in BDI agent programming languages: A formal approach. In Proceedings of AAMAS’06 (pp. 1001–1008), Hakodate.Google Scholar
  16. 16.
    Duff, S., Harland, J., & Thangarajah, J. (2006). On proactivity and maintenance goals. In Proceedings of AAMAS’06 (pp. 1033–1040), Hakodate.Google Scholar
  17. 17.
    Estlin, T., Rabideau, G., Mutz, D., & Chien, S. (2000). Using continuous planning techniques to coordinate multiple rovers. Electronic Transactions on Artificial Intelligence, 4(A), 45–57.Google Scholar
  18. 18.
    Georgeff, M., & Rao, A. (1998). Rational software agents: From theory to practice. In Agent technology: Foundations, applications, and markets (Chap. 8, pp. 139–160). New York: Springer.Google Scholar
  19. 19.
    Hindriks, K. V., van der Hoek, W., & van Riemsdij, M. B. (2009). Agent programming with temporally extended goals. In Proceedings of AAMAS’09 (pp. 137–144), Budapest.Google Scholar
  20. 20.
    Hindriks, K. V., & van Riemsdijk, M. B. (2008). Using temporal logic to integrate goals and qualitative preferences into agent programming. In Proceedings of 6th international workshop on declarative agent languages and technologies (DALT’08) (pp. 173–189), Estoril.Google Scholar
  21. 21.
    Jet Propulsion Laboratory: Mars Science Laboratory: Mission science goals. (2012). Retrieved August 2012.
  22. 22.
    Jet Propulsion Laboratory: Mars Science Laboratory/Curiosity. (2012). Tech. Rep. JPL 400–1491 8/12. National Aeronautics and Space Administration, Pasadena.Google Scholar
  23. 23.
    Khan, S. M., & Lespérance, Y. (2010). A logical framework for prioritized goal change. In Proceedings of AAMAS’10 (pp. 283–290), Toronto.Google Scholar
  24. 24.
    Lorini, E., van Ditmarsch, H. P., & Lima, T. D. (2010). A logical model of intention and plan dynamics. In Proceedings of ECAI’10 (pp. 1075–1076), Lisbon.Google Scholar
  25. 25.
    Morandini, M., Penserini, L., & Perini, A. (2009). Operational semantics of goal models in adaptive agents. In Proceedings of AAMAS’09 (pp. 129–136), Budapest.Google Scholar
  26. 26.
    Myers, K. L., & Morley, D. N. (2001). Human directability of agents. In Proceedings of first international conference on knowledge capture (K-CAP’01) (pp. 108–115), Victoria.Google Scholar
  27. 27.
    Padgham, L., & Winikoff, M. (2004). Developing intelligent agent systems: A practical guide. New York: Wiley.CrossRefGoogle Scholar
  28. 28.
    Pokahr, A., Braubach, L., & Lamersdorf, W. (2005). Jadex: A BDI reasoning engine. In Multi-agent programming (pp. 149–174). Heidelberg: Springer.Google Scholar
  29. 29.
    Rao, A. S., & Georgeff, M. P. (1992). An abstract architecture for rational agents. In Proceedings of KR’92 (pp. 439–449), Cambridge.Google Scholar
  30. 30.
    Sardiña, S., & Padgham, L. (2007). Goals in the context of BDI plan failure and planning. In Proceedings of AAMAS’07 (pp. 16–23), Honolulu.Google Scholar
  31. 31.
    Sardiña, S., & Padgham, L. (2011). A BDI agent programming language with failure handling, declarative goals, and planning. Journal of Autonomous Agents and Multi-Agent Systems, 23(1), 18–70.CrossRefGoogle Scholar
  32. 32.
    Shaw, P. H., Farwer, B., & Bordini, R. H. (2008). Theoretical and experimental results on the goal-plan tree problem. In Proceedings of AAMAS’08 (pp. 1379–1382), Estoril.Google Scholar
  33. 33.
    Siebra, C., Tate, A., & Lino, N. Q. (2004). Planning and representation of joint human-agent space missions via constraint-based models. In Proceedings of international workshop on planning and scheduling in space (IWPSS’04).Google Scholar
  34. 34.
    de Silva, L., Sardiña, S., & Padgham, L. (2009). First principles planning in BDI systems. In Proceedings of AAMAS’09 (pp. 1105–1112), Budapest.Google Scholar
  35. 35.
    Singh, D., Sardiña, S., & Padgham, L. (2010). Extending BDI plan selection to incorporate learning from experience. Robotics and Autonomous Systems, 58(9), 1067–1075.CrossRefGoogle Scholar
  36. 36.
    Thangarajah, J., Harland, J., Morley, D., & Yorke-Smith, N. (2007). Aborting tasks in BDI agents. In Proceedings of AAMAS’07 (pp. 8–15), Honolulu.Google Scholar
  37. 37.
    Thangarajah, J., Harland, J., Morley, D., & Yorke-Smith, N. (2008). Suspending and resuming tasks in BDI agents. In Proceedings of AAMAS’08 (pp. 405–412), Estoril.Google Scholar
  38. 38.
    Thangarajah, J., Harland, J., Morley, D., & Yorke-Smith, N. (2010). On the life-cycle of BDI agent goals. In Proceedings of ECAI’10 (pp. 1031–1032), Lisbon.Google Scholar
  39. 39.
    Thangarajah, J., Harland, J., Morley, D., & Yorke-Smith, N. (2010). Operational behaviour for executing, suspending and aborting goals in BDI agent systems. In Proceedings of 8th international workshop on declarative agent languages and technologies (DALT’10) (pp. 1–17), Toronto.Google Scholar
  40. 40.
    Thangarajah, J., Harland, J., Morley, D., & Yorke-Smith, N. (2011). Operational behaviour for executing, suspending, and aborting goals in BDI agent systems. In A. Omicini, S. Sardina, & W. Vasconcelos (Eds.), Declarative agent languages and technologies VIII. Lecture notes in computer science (Vol. 6619, pp. 1–21). Berlin: Springer.Google Scholar
  41. 41.
    Thangarajah, J., & Padgham, L. (2011). Computationally effective reasoning about goal interactions. Journal of Automated Reasoning, 47(1), 17–56.CrossRefMathSciNetGoogle Scholar
  42. 42.
    Thangarajah, J., Padgham, L., & Harland, J. (2002). Representation and reasoning for goals in BDI agents. In Proceedings of twenty-fifth Australasian computer science conference (ACSC’02) (pp. 259–265), Melbourne.Google Scholar
  43. 43.
    Thangarajah, J., Padgham, L., & Winikoff, M. (2003). Detecting and avoiding interference between goals in intelligent agents. In Proceedings of IJCAI’03 (pp. 721–726), Acapulco.Google Scholar
  44. 44.
    Thangarajah, J., Padgham, L., & Winikoff, M. (2003). Detecting and exploiting positive goal interaction in intelligent agents. In Proceedings of AAMAS’03 (pp. 401–408), Melbourne.Google Scholar
  45. 45.
    van Lamsweerde, A. (2001). Goal-oriented requirements engineering: A guided tour. In Proceedings of 5th IEEE international symposium on requirements engineering (RE’01) (pp. 249–263), Toronto.Google Scholar
  46. 46.
    van Riemsdijk, M. B., Dastani, M., & Meyer, J. J. C. (2005). Semantics of declarative goals in agent programming. In Proceedings of AAMAS’05 (pp. 133–140), Utrecht.Google Scholar
  47. 47.
    van Riemsdijk, M. B., Dastani, M., Meyer, J. J. C. (2005). Subgoal semantics in agent programming. In Proceedings of 12th Portuguese conference on artificial intelligence (EPIA’05) (pp. 548–559), Covilhã.Google Scholar
  48. 48.
    van Riemsdijk, M. B., Dastani, M., & Meyer, J. J. C. (2009). Goals in conflict: Semantic foundations of goals in agent programming. Journal of Autonomous Agents and Multi-Agent Systems, 18(3), 471–500.CrossRefGoogle Scholar
  49. 49.
    van Riemsdijk, M. B., Dastani, M., & Winikoff, M. (2008). Goals in agent systems: A unifying framework. In Proceedings of AAMAS’08 (pp. 713–720), Estoril.Google Scholar
  50. 50.
    Washington, R., Golden, K., Bresina, J., Smith, D. E., Anderson, C., & Smith, T. (1999). Autonomous rovers for Mars exploration. In Proceedings of IEEE aerospace conference (pp. 237–251), Aspen.Google Scholar
  51. 51.
    Winikoff, M., Dastani, M., & van Riemsdijk, M. B. (2010). A unified interaction-aware goal framework. In Proceedings of ECAI’10 (pp. 1033–1034), Lisbon.Google Scholar
  52. 52.
    Winikoff, M., Padgham, L., Harland, J., & Thangarajah, J. (2002). Declarative and procedural goals in intelligent agent systems. In Proceedings of KR’02 (pp. 470–481). Toulouse.Google Scholar
  53. 53.
    Wooldridge, M. (2002). An introduction to multiagent systems. Chichester: Wiley.Google Scholar

Copyright information

© The Author(s) 2013

Authors and Affiliations

  • James Harland
    • 1
  • David N. Morley
    • 2
  • John Thangarajah
    • 1
  • Neil Yorke-Smith
    • 3
    • 4
    Email author
  1. 1.RMIT UniversityMelbourneAustralia
  2. 2.SRI InternationalMenlo ParkUSA
  3. 3.American University of BeirutBeirutLebanon
  4. 4.University of CambridgeCambridgeUK

Personalised recommendations