Giorgos Zacharia

Trust management through reputation mechanisms

The members of electronic communities are often unrelated to each other; they may have never met and have no information on each others reputation. This kind of information is vital in electronic commerce interactions, where the potential counterparts reputation can be a significant factor in the negotiation strategy. Two complementary reputation mechanisms are investigated which rely on collaborative rating and personalized evaluation of the various ratings assigned to each user. While these reputation mechanisms are developed in the context of electronic commerce, it is believed that they may have applicability in other types of electronic communities such as chatrooms, newsgroups, mailing lists, etc.

Collaborative reputation mechanisms in electronic marketplaces

The members of electronic communities are often unrelated to each other, they may have never met and have no information on each others reputation. This kind of information is vital in electronic commerce interactions, where the potential counterparts reputation can be a significant factor in the negotiation strategy. This paper proposes two complementary reputation mechanisms that rely on collaborative ratings and personalized evaluation of the various ratings assigned to each user. While these reputation mechanisms are developed in the context of electronic commerce, we believe that they may have applicability in other types of electronic communities such as chatrooms, newsgroups, mailing lists, etc.

Evolving a multi-agent information filtering solution in Amalthaea

Amalthaea is an evolving, multiagent ecosystem for personalized ltering, discovery and monitoring of information sites. Amalthaeas primary application domain is the World-Wide-Web and its main purpose is to assist its users in nding interesting information. Two di erent categories of agents are introduced in the system: ltering agents that model and monitor the interests of the user and discovery agents that model the information sources. A market-like ecosystem where the agents evolve, compete and collaborate is presented: agents that are usefull to the user or other agents reproduce while low-performing agents are destroyed. Results from various experiments with di erent system con gurations and varying ratios of user interests vs agents in the system are presented. Finally issues like ne-tuning the initial parameters of the system and establishing and maintaining equilibria in the ecosystem are discussed.

Agent-mediated electronic commerce: an MIT media laboratory perspective

Abstract: Software agents, semi-intelligent autonomous tools, will play an increasing role in electronic commerce applications. This paper gives an overview of the work at MIT’s Media Laboratory on several types of agents for electronic commerce, ranging from consumer-to-consumer “smart” classified-ad systems to merchant agents that provide integrative negotiation capabilities, from agents that facilitate expertise brokering to distributed reputation facilities, and from point-of-sale comparison-shopping agents to mobile shopping systems.

Design methodology of an online greek language course

We present a participatory design methodology for developing an online community supported Modern Greek language course. The students of the classes collaborate in transcribing real audio lessons, publish and peer review shared notes. Participatory design was implemented as a four step process (a) Building bridges with the intended users (b) Map user needs and suggestions to the system (c) Develop a prototype (d) Integrate feedback and continue the iteration.

Amalthaea and Histos: MultiAgent Systems for WWW Sites and Reputation Recommendations

As stated in the previous chapters, recommender systems have long been a favorite application area for agent and multiagent systems researchers. The recommender systems space has traditionally been divided into systems that try to analyse the contents of documents and system that use methods other than content analysis. Content-based filtering systems are using techniques like weighed keyword vectors and SVD, while collaborative filtering and pair-wise ratings are used in the second systems category. In this chapter we will introduce two systems: Amalthaea, that falls in the former category and uses weighed keyword vectors as its representation and Histos, a pair-wise rating system that falls in the latter category.

Website content accessibility of the Cyprus domain

This paper extends previous studies that investigated the accessibility of different web sites of specific content, to an analysis of the whole web of a specific country (Cyprus). To our knowledge no previous study has analyzed such a big number of web sites for accessibility in a single study. More specifically this paper evaluates the compliance of 30,000 Cyprus related websites spidered by Arachne search engine. The 30,000 Cyprus related websites where evaluated for accessibility using the Bobby accessibility tool. Statistical analysis and comparison of the accessibility ratings for the different main domain categories (commercial, academic, governmental, and organizational) of the Cypriot web are also provided.