Communication between Vacuous AVAs

The communication between vacuous AVAs can be defined by the following pair of message exchange functions:

  

where and denote messages sent out to and via the communication network, respectively. This model has the following characteristics:

• does not depend on the receiver's state . That is, it represents an asynchronous message transfer and can support broadcast.
• , on the other hand, depends on the receiver's state . That is, while a sender submits a message at its convenience, a receiver can accept and/or reject the message depending on it own state. To implement such deliberate message processing, a message buffer should be introduced.

Note that we are not claiming that the above functions should be used for communication but just introduced them to facilitate later discussions.

Based on the functional definitions given above, we can derive the following observations about interactions among perception, action, and communication of vacuous AVAs.

1. Comparing equations (3) and (4), the action by a vacuous AVA is nothing but a special case of the reasoning. This view leads us to a new model of action. As shown in equation (4), the essence of action is the state transition. This holds also in the case of embodied AVAs, because physical body actions can be modeled by state changes of mechanical parts. Then, the world state transition caused by the action should be modeled by the side-effect of the action. Consequently, equation (2) is refined to

     

   The essential difference between embodied and vacuous AVAs rests in whether or not function is supported. Further implications of carrying a physical body will be discussed later in Section 3.3.

2. The state transition is caused by the action, the perception followed by the reasoning, and/or the message acception. Thus we can summarize these processes into

    

   Consequently, the behavior of a vacuous AVA can be modeled by equations (1), (5), and (9) (Fig. 5).

3. in equation (5) is the only one possible way to incur the state transition of other AVAs. This means that a group of vacuous AVAs can interact with each other only by the message exchange. That is, no cooperation can be realized without the message exchange.
4. To realize the cooperation between vacuous AVAs, should include and/or , where j denotes the sender AVA of .

  
Figure 5: Model of a vacuous AVA.