# Computational Accountability in MAS Organizations with ADOPT
## 2 Multiagent Systems Need Accountability  
A common way to tackle coordination in MASs is to define an organization, that is, a \"structure\", within which interaction occurs. Inspired by the human organizations, a MAS organizational model includes a specification of organizational goals, and of a functional decomposition for achieving these goals through subgoals distributed among the agents in the organization. One key notion that is used in defining an organization is that of role. Organizational roles are typically understood as a way to delegate a complex task to different principals, abstracting from the actual individuals (the agents) who will play the roles. Following [25], when adopting a role, an agent, who satisfies some given requirements, acquires some powers inside that organizational context. A power extends the agent's capabilities, allowing it to operate inside the organization and to change the organizational state. Requirements, in turn, are needed capabilities that a candidate player must exhibit to play a particular role. This definition of role follows the one given in [26] in which roles are definitionally dependent from the organization they belong to: Roles do not exist as independent entities, but rather, they are linked by definition to the organization they belong to. Typically, in organization-oriented approaches, the MAS designer focuses on the organization of the system, taking into account its main objectives, structure and social norms. OperA [2], for instance, defines an organization along three axes: An organizational model describes the desired overall behavior of the organization, and specifies the global objectives and the means to achieve them; a social model defines the agent population, maps agents to organizational roles, and defines social contracts (agreements) on role enactment; and the interaction model correlates role-enacting agents through specified interactions. OMNI [3], based on OperA, provides a top-down, layered model of organization. An abstract level describes the general aims of the organization through a list of externally observable objectives. A concrete level specifies the means to achieve the objectives identified in the abstract level. Finally, an implementation level describes the activity of the system as realized by the individual agents. In this perspective, individual agents will enact organizational roles as a means to realize their own goals. E-institutions [1] model organizations as social groups of individuals built to achieve common (shared or antagonistic) goals. Here, organizations usually provide a set of norms, which agents in the system need to follow, depending on the role they are playing. If an agent violates a norm, the system must detect the violation and act consequently, for example, applying a sanction or warning the other participants. OCeAN [4] is a conceptual framework that extends the concept of the E-institution. The authors state that a suitable meta-model for open interaction systems must comprise, besides norms, an ontology, a set of roles associated to institutional actions, and a set of linguistic conventions. Roles provide agents the capability to perform institutional actions, which are actions whose meaning and effects require a convention among participants of the system. OCeAN foresees that institutional actions are messages, whose sending is bound to an institutional action by means of a count-as relation. 2 OPL [10] is a rule-based language to define norms within a MAS, in order to achieve global goals of the system. The state of the world is represented by means of brute facts, first-order atoms, and of institutional facts which model the normative state of the system, tracing occurred violations. In Tropos [7], a MAS is seen as an organization of coordinated autonomous agents that interact in order to achieve common goals. Considering real-world organizations as a metaphor, the authors propose some architectural styles which borrow concepts from organizational theories, such as joint ventures.