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					                        Software Agent



                               Chun Tang

                         chuntang@cse.buffalo.edu




University at Buffalo                               Mar 2000
                                  Outline

              • Software Agents
                 –What is a software agent?
                 –Attributes/properties
              • Multiagent Systems
                 –Homogeneous Non-Communicating MAS
                 –Heterogeneous Non-Communicating MAS
                 –Heterogeneous Communicating MAS
              • Software Agent Technologies & KQML
              • Research in E-Commerce


University at Buffalo                                   Mar 2000
                         What is an agent?

      The American Heritage Dictionary — “an agent is one that
        acts or has the power or authority to act or represent
        another” or the “means by which something is done or
        caused, instrument.”


      The AIMA Agent — "An agent is anything that can be
        viewed as perceiving its environment through sensors and
        acting upon that environment through effectors."
      The SodaBot Agent — "Software agents are programs that
        engage in dialogs and negotiate and coordinate transfer of
        information."


University at Buffalo                                         Mar 2000
                        What is an agent?

    More than 10 different definitions are available at
     http://www.msci.memphis.edu/~franklin/AgentProg.html


    — Workers involved in agent research have offered a variety
     of definitions, each hoping to explicate his or her use of
     the word "agent." These definitions range from the simple
     to the lengthy and demanding...




University at Buffalo                                     Mar 2000
                        Attributes/Properties

        • Reactive(Sensing and acting): responds in a timely
          fashion to changes in the environment
        • Autonomous: goal-directedness, pro-active and self-
          starting behavior
        • Collaborative: can work in concert with other agents
          to achieve a common goal
        • Knowledge-level communication ability: the ability to
          communicate with persons and other agents with
          language more resembling human-like speech acts
          than typical symbol-level program-to-program protocols



University at Buffalo                                           Mar 2000
                        Attributes/Properties
• Inferential capability: can act on abstract task specification
  using prior knowledge of general goals and preferred methods
  to achieve flexibility; goes beyond the information given, and
  may have explicit models of self, user, situation, and/or other
  agents
• Temporal continuity: persistence of identity and state over
  long periods of time
• Personality/Character: the capability of manifesting the
  attributes of a believable character such as emotion
• Adaptive/Learning: being able to learn and improve with
  experience
• Mobility: being able to migrate in a self-directed way from
  one host plat-form to another
University at Buffalo                                      Mar 2000
                        Three Dimensions charactor




University at Buffalo                                Mar 2000
                        The second Typology




University at Buffalo                         Mar 2000
                        The third classification




University at Buffalo                              Mar 2000
                              Multiagent Systems

      Multiagent Systems (MAS) aims to provide both principles for
       construction of complex systems involving multiple agents and
       mechanisms for coordination of independent agents' behaviors.
      Here we consider an agent to be an entity with goals, actions, and
        domain knowledge, situated in an environment. The way it acts is
        called its ``behavior.'’




University at Buffalo                                                  Mar 2000
                        Homogeneous Non-Communicating MAS
  There are several different agents with identical structure (sensors,
    effectors, domain knowledge, and decision functions), but they have
    different sensor input and effector output.




University at Buffalo                                                Mar 2000
                        Homogeneous Non-Communicating MAS

         Reactive agents simply retrieve pre-set behaviors . Deliberative
          agents behave more like they are thinking, by searching through a
          space of behaviors, maintaining internal state and predicting the
          effects of actions.
        local views will be be more effective than global perspective ,
           otherwise all agent act the same way
        model the internal state of another agent in order to predict its
         actions
        agent alters the environment so as to affect the sensory input of
          another agent
        an agent may try to learn to take actions that will not directly help it
          in its current situation, but that may allow other similar agents to
          be more effective in the future.



University at Buffalo                                                          Mar 2000
                        Heterogeneous Non-Communicating MAS
 the agents have different goals, actions, domain knowledge and are situated
   differently in the environment having different sensory inputs and
   necessitates their taking different actions.(assumption no communication)




University at Buffalo                                                  Mar 2000
                        Heterogeneous Non-Communicating MAS

    An agents is benevolent if they are willing to help each other achieve
    their respective goals . On the other hand, the agents may be selfish and
    only consider their own goals when acting.

    Evolving agents can be useful in dynamic environments, but particularly
    when using competitive agents, allowing them to evolve can lead to
    complications.

    Goals, actions, and domain knowledge of the other heterogeneous
    agents may also be unknown and thus need modeling. Without
    communication, agents are forced to model each other strictly through
    observation.

    Designers of multiagent systems with limited resources must decide how
    the agents will share the resources.



University at Buffalo                                                     Mar 2000
                        Heterogeneous Non-Communicating MAS




    Although the current multiagent scenario does not allow for
      communication, they can somehow reach ``agreements,'' or make
      coinciding choices using features that have been seen or used before.
    When agents have similar goals, they can be organized into a team. Each
     agent then plays a separate role within the team. With such a benevolent
     team of agents, one must provide some method for assigning different
     agents to different roles.




University at Buffalo                                                   Mar 2000
                        Heterogeneous Communicating MAS




University at Buffalo                                     Mar 2000
                        Heterogeneous Communicating MAS

     In all communicating multiagent systems, and particularly in domains
       that include agents built by different designers, there must be some
       set language and protocol for the agents to use when interacting

     Consider communication capability as an ``action'' no different from
     any other. Thus within a planning framework, one can define
     reconditions and effects for communicative acts.


     Committing to another agent involves agreeing to pursue a given goal,
     possibly in a given manner, regardless of how much it serves one's own
     interests. Commitments can make systems run much more smoothly by
     providing a way for agents to ``trust'' each other




University at Buffalo                                                    Mar 2000
                        Software Agent Technologies




University at Buffalo                                 Mar 2000
                                  KQML

 performatives defined in KQML that allow "speech acts" that agents may
 use, and which provide the substrate for constructing more complex co-
 ordination and negotiation strategies




University at Buffalo                                               Mar 2000
                                            KQML

            The KQML language can be viewed as consisting of three layers:
              the content, message and communication layers,


            (tell
            : content "cost(bt, service-4, £5677)"
            : language standard prolog
            : ontology bt-services-domain
            : in-reply-to quote service-4
            : receiver customer-2
            : sender bt-customer-services)



University at Buffalo                                                    Mar 2000
                        Agent Communication in KQML




University at Buffalo                                 Mar 2000
                        Agent as Mediators in Electronic Commerce

            CBB(Consumer Buying Behavior) modal
            six fundamental stages guiding consumer buying behavior
            1.Need Identification --- awareness of consumer's needs.
            2.Product Brokering --- help determine what to buy, evaluation of
              product based on consumer's criteria
            3.Merchant Brokering --- determine who buy from , evaluation of
              Merchant
            4.Negotiation --- how to determine the terms of the transaction
              (exp. price)
            5.Purchase and Delivery
            6.Product service and Evaluation


University at Buffalo                                                         Mar 2000
                        Agent as Mediators in Electronic Commerce


            Recommender System
              use content-based filtering , collaborative-based filtering ,
              constrained-based filtering methods
            User Interface Approaches
              deal with all kinds of consumer, need remember consumer’s
              shopping habits , “trust” issue
            Negotiation Mechanism
              game theory research ; distributive / integrative Negotiation;
            Infrastructure, Languages , Protocols
              XML(extensible markup language ) is a data meta-language
              allowing for the semantic tagging of data




University at Buffalo                                                          Mar 2000
University at Buffalo   Mar 2000

				
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