Executable specification of open multi-agent systems

Abstract

Abstract. Multi-agent systems where the agents are developed by parties with competing interests, and where there is no access to an agent's internal state, are often classified as 'open'. The members of such systems may inadvertently fail to, or even deliberately choose not to, conform to the system specification. Consequently, it is necessary to specify the normative relations that may exist between the members, such as permission, obligation, and institutional power. We present a framework being developed for executable specification of open multi-agent systems. We adopt a bird's eye view of these systems, as opposed to an agent's perspective whereby it reasons about how it should act. This paper is devoted to the presentation of various examples from the NetBill protocol formalised in terms of institutional power, permission and obligation. We express the system specification in the Event Calculus and execute the specification by means of a logic programming implementation. We also give several example formalisations of sanctions for dealing with violations of permissions and obligations. We distinguish between an open multi-agent system and the procedure by which an agent enters and leaves the system. We present examples from the specification of a role-management protocol for NetBill, and demonstrate the interplay between such a protocol and the corresponding multi-agent system.

Embedding Landmarks and Scenes in a Computational Model of Institutions

“…Instead we have added pointers to related work wherever possible throughout the presentation. An extensive discussion of the relation between our framework and other normative systems, such as [2,8,11,17,19] to name but a few, can be found in [5,4].…”

Dynamic specification of open agent systems

“…In general, an agent is sanctioned when performing a forbidden action or not complying with an obligation. A few examples of sanctions will be shown presently (a more thorough treatment of sanctions may be found in [5,7]). Finally, a subject is never obliged to request the floor.…”

“…From rule (5), and the fact that s |= best candidate = S ∧ ∀S ¬holder (S ) ∧ role of (C ) = chair we have that powAssign(C , S ) ∈ T static (s). According to our initial assumption, however, in s the chair C is not empowered to assign the floor to S, that is,…”

“…A comparison of our work with commitment protocols (including [18,[32][33][34]84]), LGI, electronic institutions, Brewka's argument systems, as well as other approaches for specifying norm-governed systems, from the viewpoint of static specifications, may be found in [5,6].…”

“…We adopt a bird's eye view of a MAS, as opposed to an agent's own perspective whereby it reasons about how it should act. The presented infrastructure for dynamic specifications is an extension of our work on static specifications [5,7], and is motivated by 'dynamic argument systems' [12]. These are argument systems in which, at any point in the disputation, agents may start a meta level debate, that is, the rules of order become the current point of discussion, with the intention of altering these rules.…”