Electronic institutions are a formalism to define and analyse protocols among agents with a view to achieving global and individual goals. In this paper we elaborate on the verification of properties of electronic institutions based on the dialogues that agents may hold. Specifically, we provide a computational approach to assess whether an electronic institution is normatively consistent. In this manner, given an electronic institution we can determine whether its norms prevent normcompliant executions from happening. For this we strongly rely on the analysis of the dialogues that may occur as agents interact by exchanging illocutions in an electronic institution. 1.

Abstract. Electronic institutions are a formalism to define and analyse protocols among agents with a view to achieving global and individual goals. In this paper we propose a definition of norms for electronic institutions and investigate how these norms can be employed for verification and analysis. We offer automatic means to perform the extraction of subparts of an electronic institution in which norms hold true or can safely be avoided. These sub-parts can be used to synthesise norm-aware agents that will pursue or avoid commitments to norms. 1

A voting protocol for decision-making in virtual organizations is presented. In an agent-based virtual organization the functions of formation, management and dissolution of the organization are passed to software processes. Each phase in this life-cycle requires decision making: an ostensibly fair way for independent agents to make decisions is to take a vote. Accordingly, this paper formalizes a protocol for voting. The emphasis is on characterising the powers, permissions, obligations and even sanctions of the voters, using a norm-governed approach to agent societies. The specification language is the Event Calculus, and its animation is informative with respect to a full implementation. It is wellknown that various types of ad hoc alliance of autonomous entities require voting procedures, and a normative specification of the interactions is therefore beneficial for many aspects of self-organization and self-management.

Abstract. We propose a logic-based rendition of electronic institutions – these are means to specify open agent organisations. We employ a simple notation based on first-order logic and set theory to represent an expressive class of electronic institutions. We also provide a formal semantics for our constructs and present a distributed implementation of a platform to enact electronic institutions specified in our formalism. 1

Norms (permissions, obligations and prohibitions) offer a useful and powerful abstraction with which to capture social constraints in multi-agent systems. Norms should exclude disruptive or antisocial behaviour without prescribing the design of individual agents or restricting their autonomy. An important challenge, however, in the design and management of systems governed by norms is that norms may, at times, conflict with one another; e.g, an action may be simultaneously prohibited and obliged for a particular agent. In such circumstances, agents no longer have the option of complying with these norms; whatever they do or refrain from doing will lead to a social constraint being broken. In this paper, we present mechanisms for the detection and resolution of normative conflicts. These mechanisms, based on first-order unification and constraint solving techniques, are the building blocks of more sophisticated algorithms we present for the management of normative positions, that is, the adoption and removal of permissions, obligations and prohibitions in societies of agents. We capture both direct and indirect conflicts between norms, formalise a practical concept of authority, and model conflicts that may arise as a result of delegation. We are able to formally define classic ways for resolving conflicts such as lex superior and lex posterior.

Abstract. There is an increasing need of methodologies and software tools that ease the development of applications where distributed heterogeneous entities can participate. Multi-agent systems, and electronic institutions in particular, can play a main role on the development of this type of systems. Electronic institutions define the rules of the game in agent societies, by fixing what agents are permitted and forbidden to do and under what circumstances. The goal of this paper is to introduce an integrated development environment that supports the engineering of electronic institutions.

We present the MOdel of Organisational Change using Agents (MOCHA) as a means to formally specify, check and simulate organisations and their changes using agents. We define the structure of the organisation without making any assumptions about the internal characteristics of the agents who will populate it. We adopt a normative view of organisations, and capture a notion of social influence through relationships between roles. Ours is a flexible and expressive approach that contemplates agents taking part in multiple organisations with distinct roles and disparate (possibly conflicting) obligations. We make a distinction between the structure of an organisation and the population instantiating the organisation, and our framework allows the consequences of change in both the organisational structure and the population to be investigated. We also describe a machine-processable representation of our model and show how it can be used to support engineering activities. 1

Departament de Ciències de la Computació i Intel·ligència Artificial

In this paper we present a preliminary framework for a model of agents which are able to trade in futures and options derivatives markets. We design a basic logical model for the exchange process and extend it to depict futures and options contracts; we then evince an example scenario for our model to show the applicability of the work. 1

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