Multiagent System Technologies 

Abstract: There is a wide agreement on the use of norms in order to specify the expected behaviour of agents in open MAS. However, current norm formalisms focus on the declarative nature of norms. In order to be implemented, these norms should be translated into operational representations. In this paper we present our preliminary work on implementation of norm enforcement and issues on verifiability that highly affect this enforcement. We propose some mechanisms to be included in agent platforms in order to ease the implementation.

Abstract: In this paper we describe a new multi-agent simulation system, called Spark, for physical agents in three-dimensional environments. Our goal in creating Spark was to provide a great amount of flexibility for creating new types of agents and simulations. To achieve this, we implemented a flexible application framework and exhausted the idea of replaceable components in the resulting system. In comparison to specialized simulators, users can effortlessly create new simulations by using a scene description language. Spark is a powerful and flexible tool to state different multi-agent research questions. It is used as official simulator for the first three-dimensional RoboCup Simulation League competition. We present the concepts we used to achieve the flexibility in our system and show how we seamlessly integrated the different subsystems into one user-friendly framework.

Abstract: Peer-to-Peer systems are a new paradigm for information sharing and some systems have successfully been deployed. It has been argued that current Peer-to-Peer systems suffer from the lack of semantics. The SWAP project (Semantic Web and Peer-to-Peer) aims at overcoming this problem by combining the Peer-to-Peer paradigm with Semantic Web technologies. In this paper, we propose a data model for encoding semantic information that combines features of ontologies (concept hierarchies, relational structures) with a flexible description and rating model that allows us to handle heterogeneous and even contradictory views on the domain of interest. We discuss the role of this model in the SWAP environment and describe the model as well as its application.

Abstract: The main focus of multi-agent research so far has been on concepts and techniques to analyze and specify multi-agent systems. Much less attention has been devoted to the implementation of the con- cepts and techniques. This paper intends to bridge the gap between the mere concept of simultaneous actions and its implementation. Simultane- ous actions are actions that are executed by different agents at the same time. We study simultaneous actions in the context of situated multi- agent systems where agents and objects have an explicit position in the environment. To clarify the concept of simultaneous actions, first we propose a classification for simultaneous actions and illustrate each type with examples. Then we present a generic model for simultaneous actions that is independent of the applied agent architecture. Support for simul- taneous actions involves two aspects: first it must enable agents to act together and second, it must ensure that the outcome of a combination of simultaneously performed actions is in accordance with the domain that is modeled. In the model, acting together is established through synchro- nization, while the domain requirements are ensured through reification of actions and subsequently combining the simultaneously performed ac- tions in accordance with the valid laws. We used the model to implement the Packet-World with centralized as well as with regional synchroniza- tion. In the paper we illustrate the model for both approaches and discuss the implications for the complexity of implementation, the autonomy of agents and the scalability of the multi-agent system.