Efficient Verification of MASs with Projections

Abstract

Constrained global types are a powerful means to represent agent interaction protocols. In our recent research we demonstrated that they can be used to represent complex protocols in a very compact way, and we exploited them to dynamically verify the correct implementation of a protocol in two real MAS frameworks, Jason and JADE. The main drawback of our previous approach is the full centralization of the monitoring activity, which is delegated to a unique monitor agent. This approach works well for MASs with few agents, but could become unsuitable in communication-intensive and highly-distributed MASs where hundreds of agents should be monitored. In this paper we define an algorithm for projecting a constrained global type onto a set of agents Ags, by restricting it to the interactions involving agents in Ags, so that the outcome of the algorithm is another constrained global type that can be safely used for verifying the compliance of the sub-system Ags to the protocol specified by the original constrained global type. The projection mechanism is the first step towards distributing the monitoring activity, making it safer and more efficient: the compliance of a MAS to a protocol could be dynamically verified by suitably partitioning the agents of the MAS into small sets of agents, and by assigning to each partition Ags a local monitor agent which checks all interactions involving Ags against the projected constrained global type

Distributed Runtime Verification of JADE Multiagent Systems

“…In communication intensive MASs, the presence of agents like the JADE Sniffer and our monitor may represent a bottleneck. By implementing the monitor from scratch instead of relying on the Sniffer agent, keeping the textual interface and removing the GUI, by reducing the dimensions of the monitor's log files reporting only the identified problems, and by exploiting the projections presented in [2] that avoid bottlenecks due to the single centralized monitor, we are confident to overcome most problems related with the monitor's performance.…”

“…The framework consists of (1) a formalism for describing "agent interaction protocols" (AIPs) based on Attributes Global Types (AGT) [1,10]; (2) an algorithm to project AIPs onto subsets of agents, to obtain simpler protocols expressed in the same AGT formalism [2]; (3) a mechanism for capturing messages between the JADE agents under monitoring, in a transparent way; and (4) a method for verifying that interactions are compliant with the AIP [3].…”

Field Monitoring With Delayed Saving

“…Briola et al [32], [33] and Ancona et al [34] developed a framework for distributed runtime verification of protocols for Multi-Agent Systems (MAS). Basically, the approach splits the global interaction protocol into sub protocols and then monitors the sub protocols by transforming agent messages into Prolog predicates suitable for runtime verification.…”