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Online communities promise a new era of flexible and dynamic collaborations. However, these features also raise new security challenges, especially regarding how trust is managed. In this paper, we focus on situations wherein communities participants collaborate with each others via software agents that take trust decisions on their behalf based on policies. Due to the open and dynamic nature of Online...
Open, distributed multi-agent systems with heterogeneousagent societies face the challenge to maintain anappropriate performance level in the presence of bad-behavingagents. An approach to counter the exploiting behaviour of suchagents is the use of trust mechanisms. Yet, it is still possible foragents with a more complex behaviour to manipulate and exploitthe trust mechanism. In this paper, we show...
Self-integration in open, distributed technical systems needs a mechanism for establishing and evaluating trust relationships to work in a stable and efficient manner. Based on a case study concerned with a Trusted Desktop Grid, this paper investigates techniques to isolate malicious agents. Therefore, we introduce a novel distributed strategy to identify and accuse nonbenevolentagents. Since intentionally...
Grid systems are an ideal basis to parallelise computationally intensive tasks that efficiently can be split into parts. One possible application domain for such systems is rendering of films. Since small companies and underground film producers do not have the possibility to maintain appropriate computing environments for their own films, grid-based approaches can be used to build a self-organised...
Research in normative multi-agent systems (NorMAS) have progressed from norm representation towards investigation of mechanisms in social sciences to support for agents' tasks in open multi-agent systems (open-MAS) settings. Open-MAS characteristics pose new challenges in regulating and coordinating agents' behavior. Norms are no longer assumed to be built into agents during design time, but emerged...
In open multi-agent systems, agents may hide or lie about information regarding some events. In order to avoid such deception, a multi-agent system must be designed to test the confidence of agents. In this paper, we present a new approach to agent-based confidence modeling. This approach integrates two confidence requirements, namely, trust and certainty. We use fuzzy logic in representing the importance...
Service-oriented environments comprise a number of interconnected service providers and service consumers and are filled by vast numbers of services of various functionalities with different qualities. Finding the desirable services among others is a major problem for a typical user, who can optimize its performance by utilizing services with good qualities. This problem is sometimes addressed by...
Self-integration of system components is characterised by uncertain relations among these components. One approach to handle such uncertainties is to introduce technical trust. In previous work, we developed a concept to automatically build collections of components with stable trust relationships so-called Trusted Communities. In this paper, we discuss advanced attacks to the trusted communities...
The growing number of services available within social applications (viz. Social networks) raises a new and challenging search issue: selecting desired services from social networks. Traditional discovery and selection approaches, which are registry-based (e.g., UDDI, ebXML), have manifested their limitations as they often fall behind users' expectations. This is because registries fail to (i) take...
The goal of this paper is to create a hybrid system that will investigate possible stock market changes immediately after financial news article appear and how this information influences the stock market behavior in order to improve the profitability of a short or medium time period investment. We proposed a multi-agent system that uses text mining, information extraction, pattern recognition, sentiment...
We present self-organisation processes within a decentralised P2P open Desktop Grid System. Every agent aimsto maximise the speedup of his jobs by joining the system. Therefore he needs to cooperate with other agents. We use a trust metric to assess the willingness of cooperation for other agents. To further optimise their speedup agents can form explicit Trusted Communities with trusted peers. Thus...
Coalition formation is an important way for agents to cooperate and coordinate. By forming coalitions, agents can execute tasks efficiently and maximize their payoff in multi-agent systems. Most of existing work focuses on designing mechanisms that are based on coalition structure generation or game theory. However they ignore that as a system composed of autonomous agents, relations will play an...
Open, heterogeneous multi-agent systems (MAS) have to cope with a variety of uncertainties introduced by the systems' participants and their environment. In such systems, agents can use trust values that characterize the behavior of their interaction partners as a measure of uncertainty, allowing agents to make more appropriate decisions. However, because of the systems' dynamics and the agents' limited...
In a world where an increasing number of transactions are made on the web, there is a need for a trust evaluation tool dealing with uncertainty, e.g., for customers interested in evaluating the trustworthiness of an unknown service provider throughout queries to other customers of unknown reliability. In this paper, we propose to estimate the trust of an unknown agent, say ??^D, through the information...
Agent reasoning in large scale multi-agent systems requires techniques which often work with uncertainty and probability. In our research, we use trust and reputation principles to support agent reasoning and decisioning. Information about agents past behaviour and their qualities are transformed to multi-context trust. It allows to view a single agent from different point of views, because agents...
Interactions between individuals are inherently dependent upon trust, no matter if they occur in the real world or in cyber communities. Over the past years, proposals have been made to model trust relations computationally, either to assist users or for modeling purposes in multi-agent systems. These models rely implicitly on the social networks established by participating entities (be they autonomous...
The aim of this paper is to highlight the importance of trust and reputation in communities of practice and to describe a theoretical framework for the organization of communities of practice in a dynamic perspective. The inter-organizational behavior of communities of practice members has been researched and formalized using agent-based representation. We have proposed an adapted agent-based model...
This paper considers an adaptive data dissemination scenario that applies an autonomic trust protocol to a network of agents. The protocol uses social network structures to incentivize cooperation. Validation is conducted through simulation of content sharing between peers which uses similarity of interest between peers to define payoff. Positive correlation is observed between the number of social...
The routing performance in Mobile Ad-hoc Networks (MANETs) relies on the co-operation of the individual nodes that constitute the network. The existence of misbehaving nodes may paralyze the routing operation in MANETs. To overcome this behavior, the trustworthiness of the network nodes should be considered in the route selection process combined with the hop count. The trustworthiness is achieved...
Contract Net Protocol (CNP) is a means to specify problem-solving communication required in a distributed multi-agent environment. Although, FIPA standardized CNP addresses most of the issues with respect to communication happening among agents in a Multi-Agent Environment (MAE), issues related to establishing trust-worthy communication amongst agents is still prevailing. This work introduces a new...
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