Fuzzy argumentation for trust

In an open Multi-Agent System, the goals of agents acting on behalf of their owners often conflict with each other. Therefore, a personal agent protecting the interest of a single user cannot always rely on them. Consequently, such a personal agent needs to be able to reason about trusting (information or services provided by) other agents. Existing algorithms that perform such reasoning mainly focus on the immediate utility of a trusting decision, but do not provide an explanation of their actions to the user. This may hinder the acceptance of agent-based technologies in sensitive applications where users need to rely on their personal agents. Against this background, we propose a new approach to trust based on argumentation that aims to expose the rationale behind such trusting decisions. Our solution features a separation of opponent modeling and decision making. It uses possibilistic logic to model behavior of opponents, and we propose an extension of the argumentation framework by Amgoud and Prade to use the fuzzy rules within these models for well-supported decisions

From Manifesta to Krypta: The Relevance of Categories for Trusting Others

In this paper we consider the special abilities needed by agents for assessing trust based on inference and reasoning. We analyze the case in which it is possible to infer trust towards unknown counterparts by reasoning on abstract classes or categories of agents shaped in a concrete application domain. We present a scenario of interacting agents providing a computational model implementing different strategies to assess trust. Assuming a medical domain, categories, including both competencies and dispositions of possible trustees, are exploited to infer trust towards possibly unknown counterparts. The proposed approach for the cognitive assessment of trust relies on agents' abilities to analyze heterogeneous information sources along different dimensions. Trust is inferred based on specific observable properties (Manifesta), namely explicitly readable signals indicating internal features (Krypta) regulating agents' behavior and effectiveness on specific tasks. Simulative experiments evaluate the performance of trusting agents adopting different strategies to delegate tasks to possibly unknown trustees, while experimental results show the relevance of this kind of cognitive ability in the case of open Multi Agent Systems

Veto-Based Delegation

In a principal-agent model with hidden information and no monetary transfers, I establish the Veto-Power Principle: any incentive-compatible outcome can be implemented through veto-based delegation with an endogenously chosen default decision. This result demonstrates the exact nature of commitment powers required by the principal: (1) to design the default outcome and (2) to ensure that she has almost no formal control over the agent's decisions

On Rational Delegations in Liquid Democracy

Liquid democracy is a proxy voting method where proxies are delegable. We propose and study a game-theoretic model of liquid democracy to address the following question: when is it rational for a voter to delegate her vote? We study the existence of pure-strategy Nash equilibria in this model, and how group accuracy is affected by them. We complement these theoretical results by means of agent-based simulations to study the effects of delegations on group's accuracy on variously structured social networks.Comment: 17 pages, 3 figures. This paper (without Appendix) appears in the proceedings of AAAI'1

Self-Configuring Socio-Technical Systems: Redesign at Runtime

Modern information systems are becoming more and more socio-technical systems, namely systems composed of human (social) agents and software (technical) systems operating together in a common environment. The structure of such systems has to evolve dynamically in response to the changes of the environment. When new requirements are introduced, when an actor leaves the system or when a new actor comes, the socio-technical structure needs to be redesigned and revised. In this paper, an approach to dynamic reconfiguration of a socio-technical system structure in response to internal or external changes is proposed. The approach is based on planning techniques for generating possible alternative configurations, and local strategies for their evaluation. The reconfiguration mechanism is presented, which makes the socio-technical system self-configuring, and the approach is discussed and analyzed on a simple case study

Performance Pay, Delegation, and Multitasking under Uncertainty and Innovativeness An Empirical Investigation

The existing empirical evidence is somewhat inconclusive with respect to a number of the key predictions of the agency model. Although the reach of agency theory is considerably wider, the dominant portion of work has been taken up with examining the nature of the trade-off between risk and incentives, and the implications thereof for contractual design. More specifically, some researchers have recently noted that the predicted trade-off between risk and incentives turns out to be rather weak, and perhaps non-existent, when confronted with the available empirical evidence. In this paper, we examine the risk-incentives trade-off and related predictions from agency theory on the basis of data from a data set encompassing close to 1000 Danish firms. We find that the relation between the use of performance pay in these firms and the environmental uncertainty they confront which is one way to test the risk/incentives tradeoff is indeed weak and in many cases even perverse. We then suggest, in line with other recent contributions to the literature, that this may be caused by the widespread use of delegation. One effect of delegation is that it breaks the simple relation between risks and incentives. We examine the suggestion that that those firms that are more prone to use delegation of decision rights in their internal organization are facing an uncertain environment to a larger extent than the rest of the population. We argue that this constitutes an indirect confirmation of the hypothesis. We also examine the multi-tasking agency hypothesis that as risk increases, the flexibility of agents is restricted. We fail to find support for this hypothesis. It is suggested that the reason for this finding is also related to delegation.Uncertainty, pay-for-performance, delegation, innovation, competition