Trust In Multi-agent Systems Research Articles

Controller-Based Interactive Proof to Ensure Trust in Multiagent Systems

When multiple agents need to perform tasks that need cooperation, communication is necessary for coordination and also to assess completion. In this case, trust needs to be guaranteed, so agents know if others are following a common strategy. If communication is explicit, other agents, including agents that are not involved directly in the mission, can forge information and lead agents to believe that they are behaving according to the mission plan. Several methods have been proposed in the literature, and in this article, we propose a novel method based on interactive proofs in which trust between two agents is asserted by one agent demonstrating to the other that both follow the same mission plan. We formally represent the problem as a series of Markov decision processes and demonstrate that the formulation is complete and sound. Simulations of multiple agents in a maze problem demonstrate the behavior of the system.

Transformation-based model checking temporal trust in multi-agent systems

Several formal trust frameworks have been introduced in the area of Multi-Agent Systems (MASs). However, the problem of model checking trust logics is still a challenging research topic. In this paper, we address this challenge by proposing a formal and fully automatic model checking technique for two temporal logics of trust. We start by reviewing TCTL, a Computation Tree Logic of Trust, which has been recently proposed. We also introduce TCTLC for conditional trust. Then, we introduce sound and complete transformation-based algorithms that automatically transform the problem of model checking TCTL and TCTLC into the problem of model checking CTL. Moreover, we prove that although TCTL and TCTLC extend CTL, their model checking algorithms still have the same time complexity for explicit models, which is P-complete with regard to the size of the model and length of the formula, and the same space complexity for concurrent programs, which is PSPACE-complete with regard to the size of the components of these programs. Finally, experiments conducted on a standard industrial case study of auto-insurance claim processing demonstrate the efficiency and scalability of our approach in verifying TCTL and TCTLC formulae.

Formal verification of group and propagated trust in multi-agent systems

Formal verification of group and propagated trust in multi-agent systems

A Dynamic Bayesian Network approach for agent group trust evaluation

Trust, an essential concept in human society, plays a crucial role in multi-agent systems by giving agents the confidence in making decisions as well as maintaining the well-being of transactions in the systems. Research of trust in multi-agent systems has focused heavily on trust evaluation of individual agents. When agent groups are becoming essential parts of agent society, existing trust models have shown several defects in addressing the highly dynamic behaviours of these targets. To this end, this paper presents a Dynamic Bayesian network Approach for Trust Evaluation (DBATE). It combines personalised criteria with multiple observations obtained from the interaction context to reveal the trustworthiness of the evaluated targets. We demonstrate the advantages of the model in enhancing the accuracy of trust computation as well as potential applications compared with other methods.

Specification and automatic verification of trust-based multi-agent systems

We present a new logic-based framework for modeling and automatically verifying trust in Multi-Agent Systems (MASs). We start by refining TCTL, a temporal logic of trust that extends the Computation Tree Logic (CTL) to enable reasoning about trust with preconditions. A new vector-based version of interpreted systems is defined to capture the trust relationship between the interacting parties. We introduce a set of reasoning postulates along with formal proofs to support our logic. Moreover, we present new symbolic model checking algorithms to formally and automatically verify the system under consideration against some desirable properties expressed using the proposed logic. We fully implemented our proposed algorithms as a model checker tool called MCMAS-T on top of the MCMAS model checker for MASs along with its new input language VISPL (Vector-extended ISPL). We evaluated the tool and reported experimental results using a real-life scenario in the healthcare field.

Reasoning about Trust and Time in a System of Agents

Abstract: The study of trust in Multi-Agent Systems (MASs) has been an area of interest for many researchers over the last years. This is due to the fact that trust is the basis for agent communication wherein entities have to operate in a dynamic and uncertain environment. Several approaches have been proposed to define logical semantics for trust in MASs. However, these approaches are limited to reason about trust based on the sole agents’ mental states. Therefore, this paper considers trust from a high-level abstraction based on the social correct behaviors of agents. Specifically, we propose a logical framework that allows us to reason about unconditional trust and time. In particular, we introduce a new logical language called Trust Computation Tree logic (TCTL) that extends the Computation Tree Logic (CTL) with a new modality to represent trust. We describe the semantics by extending the interpreted systems formalism and consider a set of reasoning rules along with proofs to support our logic. Finally, we evaluate our approach using a real-life case study in the e-business domain to explain our proposed logic in a practical application.

A reputation-oriented trust model for multi-agent environments

Purpose – The purpose of this paper is to enhance trust in multi-agent systems by presenting a new computational model, named reputation-distribute-conflict (R-D-C), to select the most trustworthy provider agent based on computing reputation, disrepute, and conflict of each provider agent. Design/methodology/approach – R-D-C propose based on three vital components for evaluating trustworthiness of providers as reputation, disrepute, and conflict, where disrepute is a component almost all trust models ignored. The R-D-C model presents a computational method for evaluating to select the most trustworthy provider agent. In order to evaluate the R-D-C model, the experimentation was carried out in two stages, by designing a simulated multi-agent environment. First, the accuracy of the R-D-C model in computing R-D-C was investigated. Second, the performance of the model was compared with other existing trust models. Moreover, comparison of the performance of the R-D-C model with other models demonstrates that t...

Introduction to special section on trust in multiagent systems

Introduction to special section on trust in multiagent systems

Security applications of trust in multi-agent systems

The concept of trust as presented here focuses on the trustworthiness, or reliability, of information and information sources. Decision makers, or agents, can create judgments based on previous experience with other agents and by reputation information received from allied agents. These judgments, or trust assessments, are used to predict the behavior of other agents and analyze the trustworthiness, truthfulness, or quality of information. Research concepts have been developed within the trust community, and they are most commonly applied to multi-agent systems research. This work attempts to show that trust research can be directly applied to security problems. Modern trust concepts enforce soft security which can be applied in addition to conventional security methods to build a more robust secure system. This article examines two trust based techniques and demonstrates their basic effectiveness using empirical experimentation. These techniques are then applied in a case study drawn from a more robust domain concerning confidential message transmission. The benefits of applying trust-based techniques to secure a system are measurable, and the costs associated with such techniques are scalable to even the most resource constrained systems.

Using asymmetric keys in a certified trust model for multiagent systems

We present a contribution based on encryption to the model for the certification of trust in multiagent systems. The originality of the proposal remains in the use of asymmetric keys that allow the local storage of testimonies with the service agents that were assessed. The aim is to raise the level of efficiency that client agents have when contracting specialized service agents. To reach this objective we make three hypotheses: (i) client agents are able to measure and inform the quality of a service they receive from a service agent; (ii) distributed certificate control is possible if every service agent stores the certificates it receives from its client agents and, (iii) the content of a certificate can be considered safe as long as the public and private keys used to encrypt the certificate remain safe. This approach reduces some weak points of trust models that rely on the direct interaction between service and client agents (direct trust) or those that rely on testimony obtained from client agents (propagated trust). Simulation showed that encrypted certificates of trust improved the efficiency of client agents when choosing their service provider agents. The reason seems to be that the reputation of a given service provider agent is based on the reputation it has among the totality of client agents that used its services.

A Review on Computational Trust Models for Multi-agent Systems

Trust plays important roles on effective interaction and cooperation for multi-agent systems(MAS). This study aims at finding out the current situation and future trends of computational trustfor multi-agent systems. Through defining seven common compositional elements for the computational trust models, the study points out significant weaknesses in the current design. Finally, the paper figures out the future research trends through discussion and analysis around the strengths and weaknesses identified. Also the paper proposes an idea of using ontology and XML technologies such as RDF that allow systems to provide both human and machine readable annotations for trust models.

Trust in multi-agent systems

Trust is a fundamental concern in large-scale open distributed systems. It lies at the core of all interactions between the entities that have to operate in such uncertain and constantly changing environments. Given this complexity, these components, and the ensuing system, are increasingly being conceptualised, designed, and built using agent-based techniques and, to this end, this paper examines the specific role of trust in multi-agent systems. In particular, we survey the state of the art and provide an account of the main directions along which research efforts are being focused. In so doing, we critically evaluate the relative strengths and weaknesses of the main models that have been proposed and show how, fundamentally, they all seek to minimise the uncertainty in interactions. Finally, we outline the areas that require further research in order to develop a comprehensive treatment of trust in complex computational settings.

Belief, information acquisition, and trust in multi-agent systems—A modal logic formulation

In this paper, we consider the influence of trust on the assimilation of acquired information into an agent's belief. By use of modal logic, we semantically and axiomatically characterize the relationship among belief, information acquisition and trust. The belief and information acquisition operators are respectively represented by KD45 and KD normal modalities, whereas trust is denoted by a modal operator with minimal semantics. One characteristic axiom of the basic system is if agent i believes that agent j has told him the truth of p and he trusts the judgement of j on p, then he will also believe p. In addition to the basic system, some variants and further axioms for trust and information acquisition are also presented to show the expressive richness of the logic. The applications of the logic to computer security and database reasoning are also suggested by its connection with some previous works.