Inferring Trust Based on Similarity with TILLIT

Abstract

Abstract.A network of people having established trust relations and a model for propagation of related trust scores are fundamental building blocks in many of todays most successful e-commerce and recommendation systems. However, the web of trust is often too sparse to predict trust values between non-familiar people with high accuracy. Trust inferences are transitive associations among users in the context of an underlying social network and may provide additional information to alleviate the consequences of the sparsity and possible cold-start problems. Such approaches are helpful, provided that a complete trust path exists between the two users. An alternative approach to the problem is advocated in this paper. Based on collaborative filtering one can exploit the like-mindedness resp. similarity of individuals to infer trust to yet unknown parties which increases the trust relations in the web. For instance, if one knows that with respect to a specific property, two parties are trusted alike by a large number of different trusters, one can assume that they are similar. Thus, if one has a certain degree of trust to the one party, one can safely assume a very similar trustworthiness of the other one. In an attempt to provide high quality recommendations and proper initial trust values even when no complete trust propagation path or user profile exists, we propose TILLIT -a model based on combination of trust inferences and user similarity. The similarity is derived from the structure of the trust graph and users' trust behavior as opposed to other collaborative-filtering based approaches which use ratings of items or user's profile. We describe an algorithm realizing the approach based on a combination of trust inferences and user similarity, and validate the algorithm using a real large-scale data-set.

CRM: An efficient trust and reputation model for agent computing

“…The reason behind this simplification is that our main contribution in this paper is to equip the agents to efficiently evaluate the trust and get adapted with continuous environment changes. Although the domain is important in trust evaluation (as mainly considered in some trust-based frameworks [26,7]), in this paper we only focus on the adaptation of agents with dynamically changing environment and on how agile the agent is while acting where the trust evaluation is crucial. Furthermore, although the time is omitted from the formulation, it is implicitly represented as the trust function is continuous over T .…”

“…In this section, we analyze some recently emerged systems like TRSIM [6], Repage [21], Formal [30], and HIT [29]. We also analyze and compare some related robust frameworks like [7,26,14]. These models are worthy to be discussed in terms of their attempt to address the trust establishment in a different perspective.…”

“…Moreover, they do not have policies for dealing with malicious agents. Considering the ad hoc network and human concept of trust represented in [29], there is a similar framework represented in [26] that considers the similarity (of interactions) in trust. In this framework, if an agent relies on another agent with respect to a strong history of interactions, the agent can also rely on another agent that looks alike the first one in trust features.…”

“…In this framework, if an agent relies on another agent with respect to a strong history of interactions, the agent can also rely on another agent that looks alike the first one in trust features. The heuristics used in [26] are analyzed with subjective logic that enhance the agents evaluation mechanism with respect to time and number of interactions. Our framework does not consider the similarity issue, but adding it is in our future work plan.…”

Subjective logic based trust model for geographic routing in mobile ad hoc networks

“…The context specification has to be dynamic to accommodate the changes in the system and environment. The trust management strategy should be situationspecific to act accordingly [3,4]. The concept of context is essential for developing trust-based security architecture, particularly for a network with a dynamic configuration such as MANET [5].…”