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Patterns for Designing Agent-Based E-Business Systems
Figure 10. Collaboration diagram for the agent-based online auction example
events regarding the current auction (e.g., if they are winning or losing the auction). While buyer agents only notify a user about the current auc-WLRQQRWL¿HUDJHQWV²NOTIFICATIONAGENT—can be used to monitor other auctions on a user’s behalf. 7KHXVHUFUHDWHVDQRWL¿HUDJHQWE\LQLWLDOL]LQJLW ZLWKDVSHFL¿FDWLRQRIWKHSURGXFWRUVHUYLFHVKHLV looking for. On receiving a NOTIFICATION about an auction, a user can decide to create a new buyer agent to join it.
Locating Sellers by Product or Service
This example switches the positions of buyer and seller agents in the online auction example. Bob wants to buy a certain product or service and, via his USER AGENT, creates a BUYER AGENT and LQLWLDOL]HVLWZLWKDVSHFL¿FDWLRQRIWKHSURGXFW or service. This buyer agent queries a MEDIATOR AGENT—in this case, a search agent or a directory agent—for the locations of sellers for the product or service in question. At this architectural level, we could use static or mobile agents to represent buyer agents. Greengrass et al. (1999) describe a mobile agent scenario in which a buyer agent moves to the known site of a directory agent, que-ries this directory agent, and obtains an itinerary of the locations ofSELLER AGENTS to visit. Fonseca et al. (2001) document a mobile shopping system,
where an agent representing a shopper in a mall contacts a directory facilitator agent on entry to the mall, and obtains directions to stores which carry products of interest to the user, provides those directions to the user, and allows him to check the prices of other stores. For further details on this case study, and an illustration of how the patterns can be used as part of a pattern-driven design process, see Weiss (2003).
Customizing Navigation
Another example is using agents to assist users in navigating through an (online) product cata-log. From a front-end perspective, a USER AGENT FDQEHXVHGWRFROOHFWSUR¿OHLQIRUPDWLRQDERXW a user and control how this information is made DYDLODEOHWRVHOOHUDJHQWV7KHSUR¿OHLQIRUPDWLRQ IRUGLIIHUHQWVHOOHUVLVVWRUHGLQDSHUVRQDOSUR¿OH repository in the user agent—USERPROFILING. Sec-WLRQVRIWKHSUR¿OHFDQEHUHVWULFWHGWRDVXEVHWRI WKHVHOOHUVRQO\8VLQJWKHSUR¿OHLQIRUPDWLRQWKH VHOOHUDJHQWFDQFODVVLI\WKHXVHULQWRSUHGH¿QHG VWHUHRW\SHVDQGWKXVLQIHUDSUR¿OHRISURGXFWSUHI-erences—USER PROFILING. With these preferences, a product extractor agent—CATALOGING—can tailor the contents of the product catalog, such as in the personalized Web store in Ardissono HWDO,QDGGLWLRQWR¿OWHULQJWKHFDWDORJ FRQWHQWVDJDLQVWWKHEX\HU¶VSUR¿OHWKHSURGXFW
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Patterns for Designing Agent-Based E-Business Systems
extractor can propose discounts to retain existing or attract new customers.
Although we have focused on using user pro-¿OHVLQWKHIURQWHQGWKLVLVQRWWRVD\WKDWWKH\ cannot equally be used in the back-end. However, the basic trade-off in this case is that users will have OHVVFRQWURORYHUSUR¿OHVFROOHFWHGDQGVWRUHGE\ sellers. Customers may decide to do business with VHOOHUVZKRGRQRWFROOHFWSUR¿OHVLQWKLVZD\RU PDNHWKHSURFHVVRIFROOHFWLQJSUR¿OHVWUDQVSDUHQW DQGWKHSUR¿OHVWKHPVHOYHVDFFHVVLEOH
CONCLUSION
In this chapter, we described a group of ar-chitectural patterns for designing agent-based e-business systems and gives several examples illustrating their use. These patterns relate to front-end e-business activities that involve in-teraction with the user and delegation of tasks from users to agents. Future work will describe patterns for back-end e-business activities that do not involve direct interaction with the user, but rather depict mechanisms for mediating between agents representing users. These patterns will expand on the description of mediator agents in this chapter. Together, these patterns are just the beginnings of a pattern language for agent-based e-business system design, based on our current understanding of the technology. As the use of agent technology in e-business matures, this lan-guage will evolve as well. It is our hope that the proposed set of patterns and the pattern format may provide a starting point for future effort in this direction.
FUTURE RESEARCH DIRECTIONS
To date, only a subset of the patterns of agent-based e-business systems have been documented. This provides many opportunities for future research. These opportunities can be grouped into two areas.
On one hand, a better understanding of using agent patterns as part of a pattern-driven design process (Weiss, 2003) is required; we need to be able to reason about design trade-offs between patterns; see Mussbacher, Amyot, and Weiss (2007) for a typical approach and survey of related efforts, and capture pattern knowledge in pattern repositories (Knublauch & Rose, 2002) that can be consulted E\GHYHORSHUVWRDGGUHVVVSHFL¿FGHVLJQSUREOHPV during the development of an agent-based system. )LQDOO\ZHZDQWWRJHQHUDWHFRGHIRUVSHFL¿F agent frameworks from those patterns.
On the other hand, many more agent patterns in the e-business domain remain to be mined and documented. Areas of particular interest are pat-terns where agents are used as mediators, ranging from directory agents to sophisticated broker and market maker agents (Deugo et al., 2001), and pat-terns for agents that provide mobile, context-aware services. One example of current research in this area is a set of auction patterns documented by Jureta, Faulkner, and Kolp (2005). However, this would also include patterns for search, reputation management, and integration. A taxonomy of e-business agents, which could provide a suitable starting point for a systematic mining effort is given in Papazoglou (2001).
Conceptual frameworks for these activities are also required. Weiss (2003) proposes a pat-tern-driven design framework for harvesting recurring design solutions and documenting them as patterns, and guiding the designer through the VHOHFWLRQRISDWWHUQVDSSURSULDWHWRWKHLUVSHFL¿F GHVLJQFRQWH[W7KHDSSURDFKVXJJHVWVD¿YHVWHS SURFHVVWKH¿UVWWKUHHUHODWHGWRPLQLQJSDWWHUQV identify the forces in a domain, document the roles of pattern participants, and document pat-terns and their dependencies. The last two apply to patterns: identify the overall design goals and select patterns.
Finally, we need to document patterns for nonfunctional design issues such as deployment, scalability, and security of agent-based e-business systems, and we must gain a better understanding
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Patterns for Designing Agent-Based E-Business Systems
of how to integrate such patterns with the current agent development processes. Some progress along these lines has been made in the area of agent security patterns. A good starting point is Mouratidis et al. (2006).
ACKNOWLEDGMENT
An earlier version of this chapter was accepted for PLoP 2001 (Weiss, 2001). Thanks go to my shepherd Dirk Riehle for his valuable comments. 7KHPDWHULDOLQWKLVFKDSWHUKDVEHQH¿WHGIURP feedback in several tutorials and classes held since RQWKLVPDWHULDODQGZDVH[SDQGHGWRUHÀHFWWKH recent progress in the area of agent patterns.
REFERENCES
Alexander, C. (1979). The timeless way of build-ing. Oxford University Press.
Aranguren, M. (2005).Ontology design patterns for the formalisation of biological ontologies. Master’s Thesis, Manchester University.
Ardissono, L., Barbero, C., et al. (1999). An agent architecture for personalized Web stores. In Proceedings of the Conference on Autonomous Agents (pp. 182-189). ACM.
Aridor, Y., & Lange, D. (1998). Agent design patterns: Elements of agent application design. In Proceedings of the Conference on Autonomous Agents (pp. 108-115). ACM.
AuctionWatcher (2002). Retrieved August 14, 2007, from http://www.auctionswatch.info
Avgeriou, P., & Zdun, U. (2005). Architectural patterns revisited: A pattern language. In Pro-ceedings of the European Conference on Pattern Languages of Programs.
Brenner, W., Zarnekow, R., & Wittig, H. (1998). Intelligent software agents: Foundations and applications. Springer.
Carlson, D. (2001). Modeling XML applications with UML: Practical e-business applications. Addison-Wesley.
Collis, J., & Lee, L. (1999). Building electronic marketplaces with the ZEUS agent tool-kit. Lec-WXUH1RWHVLQ$UWL¿FLDO,QWHOOLJHQFH 1-24.
Deugo, D., Weiss, M., & Kendall, E. (2001). Reusable patterns for agent coordination. In A. Omicini et al. (Eds.), Coordination of Internet Agents (pp. 347-368). Springer.
Ferber, J. (1999). Multi-agent systems: An intro-GXFWLRQWRGLVWULEXWHGVUWL¿FLDOLQWHOOLJHQFH (pp. 13-16). Addison-Wesley.
Fonseca, S., Griss, M., & Letsinger, R. (2001). An agent-mediated e-commerce environment for the mobile shopper (HP Labs Tech. Rep. No. HPL-2001-157).
Greengrass, E., Sud, J., & Moore, D. (1999, June). Agents in the virtual marketplace: Component dtrategies. In Proceedings of SIGS (pp. 42-52).
Griss, M. (1999). My agent will call your agent ... but will it respond? (HP Labs Tech. Rep. No. HPL-1999-159).
Guttman, R., & Maes, P. (1999). Agent-mediated integrative negotiation for retail electronic com-merce. /HFWXUH1RWHVLQ$UWL¿FLDO,QWHOOLJHQFH 1571, 70-90.
Jureta, I., Faulkner, S., & Kolp, M. (2005). Best practices agent patterns for on-line auctions. In Proceedings of the International Conference on Enterprise Information Systems (pp. 814-822).
Kendall, E. (1999). Role models: Patterns of agent system analysis and design. InProceedings of the Agent Systems and Applications/Mobile Agents. ACM.
Kendall, E., Murali Krishna, P., Pathak, C., et al (1998). Patterns of intelligent and mobile agents. InProceedings of the Conference on Autonomous Agents. ACM.
2386
Patterns for Designing Agent-Based E-Business Systems
Kolp, M., Giorgini, P., & Mylopoulos, J. (2001). A goal-based organizational perspective on multi-agent architectures. In Proceedings of the Workshop on Agent Theories, Architectures, and Languages (LNCS 2333, pp. 128-140). Springer.
Lieberman, H. (1998). Integrating user interface agents with conventional applications. Paper presented at the Conference on Intelligent User Interfaces. ACM.
Lind, J. (2002). Patterns in agent-oriented software engineering. In Proceedings of the Workshop on Agent-Oriented Software Engineering (LNCS 2585, pp. 45-58). Springer.
Maes, P. (1994, July). Agents that reduce work and information overload. Communications of the ACM, pp. 31-41.
Mouratidis, H., Weiss, M., & Giorgini, P. (2006). Modelling secure systems using an agent-oriented approach and security patterns. International Journal on Software Engineering and Knowledge Engineering, 16(3), 471-498.
Mussbacher, G., Amyot, D., & Weiss, M. (2007). Formalizing patterns with the user requirements notation. In T. Taibi (Ed.),Design Pattern Formal-ization Techniques. Hershey, PA: IGI Global.
Noriega, P., & Sierra, C. (1999). Agent-mediated electronic commerce./HFWXUH1RWHVLQ$UWL¿FLDO Intelligence, 1571. Springer.
Papazoglou, M. (2001, April). Agent-oriented technology in support of e-business. Communica-tions of the ACM, pp. 71-77.
Reich, J. (2000). Ontological design patterns: Modelling the metadata of molecular biological ontologies, information and knowledge. Paper presented at the Conference on Database and Expert System Applications.
Riehle, D., & Gross, T. (1998). Role model based framework design and integration. InProceedings
of theConference on Object-Oriented Programs, Systems, Languages, and Applications (pp. 117-133). ACM.
Schelfthout, K., Coninx, T., et al (2002). Agent implementation patterns. Paper presented at the OOPSLA Workshop on Agent-Oriented Meth-odologies.
Shu, S., & Norrie, D. (1999).Patterns for adaptive multi-agent systems in intelligent manufacturing. Paper presented at the International Workshop on Intelligent Manufacturing Systems.
Staab, S., & Stuckenschmidt, H. (Eds.). (2006). Semantic Web and peer-to-peer. Springer.
Steinmetz, E., Collins, J., Jamieson, S., et al. (1999). Bid evaluation and selection in the MAG-NET automated contracting system. Lecture Notes LQ$UWL¿FLDO,QWHOOLJHQFH, 105-125.
Tahara, Y., Oshuga, A., & Hiniden, S. (1999). Agent system development method based on agent patterns. Paper presented at the International Conference on Software Engineering. ACM.
Ulmer, D. (2004). Architectural solutions to agent-enabling e-commerce portals with pull/ push abilities. Unpublished doctoral thesis, Pace University.
Voss, A., & Kreifelts, T. (1997). SOaP: Social agents providing people with useful information. Paper presented at the Conference on Supporting Groupwork. ACM.
W3C. (1997). 2SHQSUR¿OLQJVWDQGDUG(version 1.0, note 1997/6).
Weiss, M. (2001). Patterns for e-commerce agent architectures: Agents as delegates. Paper pre-sented at the Conference on Pattern Languages of Programs.
Weiss, M. (2003). Pattern-driven design of agent systems: Approach and case study. In Proceed-ings of theConference on Advanced Information System Engineering (pp. 711-723). Springer.
2387
Patterns for Designing Agent-Based E-Business Systems
Weiss, M. (2004). A pattern language for mo-tivating the use of agents. In Agent-Oriented Information Systems: Revised Selected Papers (LNAI 3030, pp. 142-157). Springer
Weiss, M., Gray, T., & Diaz, A. (1997). Experi-ences with a service environment for distributed multimedia applications. feature interactions in telecommunications and distributed systems, IOS, 242-253.
Wooldridge, M., & Jennings, N. (1995). Intelli-gent agents: Theory and practice. The Knowledge Engineering Review, 10(2), 115-152.
Zacharia, G., Moukas, A., & Maes, P. (1999).Col-laborative reputation mechanisms in electronic marketplaces. Paper presented at the Hawaii International Conference On System Science. IEEE.
Zambonelli, F., Jennings, N., et al. (2001). Agent-oriented software engineering for Internet applica-tions. In A. Omicini, et al. (Eds.), Coordination of Internet Agents (pp. 326-346). Springer.
on Agent Systems and Applications/Mobile Agents. Retrieved August 15, 2007, from http://www.scs. carleton.ca/~deugo/Patterns/Agent/Presentations/ AgentPatterns
Jureta, I., Faulkner, S., & Kolp, M. (2005). Best practices agent patterns for on-line auctions. In-ternational Conference on Enterprise Information Systems (pp. 814-822).
Knublauch, H., & Rose, T. (2002). Tool-supported process analysis and design for the development of multiagent systems. Workshop on Agent-Ori-ented Software Engineering (LNCS 2585, pp. 186-197). Springer.
Mussbacher, G., Amyot, D., & Weiss, M. (2007). Formalizing patterns with the user requirements notation. In T. Taibi (Ed.),Design Pattern Formal-ization Techniques. Hershey, PA: IGI Global.
ENDNOTE
1
ADDITIONAL READING
It is customary to indicate references to patterns through a SMALL CAPS font.
Deugo, D., Kendall, E., & Weiss, M. (1999). Agent pPatterns. Tutorial at the International Symposium
This work was previously published in Agent Systems in Electronic Business, edited by J. Wang, pp. 1-24, copyright 2008 by Information Science Reference (an imprint of IGI Global).
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