# The Role of Multi-Agent Systems in Realizing Asset Administration Shell Type 3
## 4 Agent-Based Reference Model for Realizing AAS Type 3
### Overview  
To develop the proposed reference model, a three-step methodology was adopted. First, a literature review was conducted to identify existing approaches integrating AAS and MAS, as discussed in the previous section. Second, these approaches were analyzed to extract common architectural patterns and design guidelines. Third, based on the most frequently observed principles and structures, a generic and reusable reference model was synthesized to guide the development of agent-based AAS solutions, with particular emphasis on supporting AAS Type 3 capabilities. Additionally, the proposed model (see Figure 5) is designed as a modular extension of the traditional AAS structure [10]. Rather than replacing existing AAS Type 1 or Type 2 implementations, the model builds upon them by introducing an intelligent layer that enables autonomy, collaboration, and adaptive behavior. This modularity allows existing AAS-based solutions to be incrementally extended toward AAS Type 3 capabilities, enhancing their functionality without requiring a complete architectural redesign. As shown in Figure 5, the defined reference model comprises two complementary parts: the information part and the intelligent part. The information part consists of a structured collection of submodels, which encapsulate detailed asset-specific information. These submodels provide a standardized knowledge base and serve as a comprehensive information source that supports agents in their decision-making processes and effective collaboration within industrial environments. On the other hand, the intelligent part is conceptualized as an agent that embodies the intelligent capabilities required for AAS Type 3. This agent is responsible for interpreting and processing the information stored in the submodels, making decisions, and executing appropriate actions. Moreover, it facilitates collaboration by communicating and negotiating with other agents, enabling decentralized coordination and adaptive behavior. In summary, the intelligent part goes beyond generic AAS requirements by integrating autonomous decision-making and agent-based collaboration capabilities, which are not formalized in existing AAS specifications but are essential for realizing the full vision of AAS Type 3. As part of the model, a set of design guidelines have been defined to characterize the development of AAS Type 3. These guidelines serve as design principles and requirements, ensuring that any developed solution aligns with the conceptual and technical expectations of AAS Type 3. These guidelines are as follows:  
* AAS Type 3 has an associated asset (individual or composite). * AAS Type 3 provides one or more I4.0-conform interface(s). * AAS Type 3 lists one or more submodel(s). * AAS Type 3 uses information from submodels to support decision-making processes, enabling autonomous behavior and intelligent responses. * AAS Type 3 collaborates with other AAS(s) Type 3 (e.g., through negotiation)
* AAS Type 3 has one or more intelligent behavior(s), e.g., based on AI techniques. * AAS Type 3 interfaces with the asset, e.g., to collect operational data or adapt control. * The information and intelligent parts can be deployed together or separately, depending on the system architecture and deployment requirements. * Submodels reference the asset services provided by an asset via an asset integration and other related services (e.g., based on AI techniques). * The user application(s) accesses the information of the AAS Type 3 via IT interfaces. * The submodel template guides the creation of a standardized submodel. * The submodel template may reference concept dictionaries and ontologies. * Concept dictionaries and ontologies define the common vocabulary. * Existing AAS Type 1 and Type 2 specifications and standards guide the development of the information part of AAS Type 3. * The AAS responsible creates and governs the AAS Type 3. Figure 5: Proposed reference model for AAS Type 3 using Multi-Agent Systems.