Michalis Sfakakis

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We compare the usage of a Digital Library with many different categories of collections, by examining its log files for a period of twenty months, and we conclude that the access points that the users mostly refer to, depend heavily on the type of content of the collection, the detail of the existing meta-data and the target user group. We also found that(More)
The interest in the analysis of library user behavior has been increasing rapidly, since the advent of digital libraries and Internet. In this context, we analyze the queries posed to a digital library and recorded into the Z39.50 session log files and we construct communities of users with common interests, using data mining techniques. One of our main(More)
The wide adoption of the Z39.50 protocol from the Libraries exposes their abilities to participate in a distributed environment. In spite of the protocol specification of a unified global access mechanism, query failures and/or inconsistent answers are the pending issues when searching many sources due to the variant or poor implementations. The elimination(More)
A graph of Access Points can be used as a tool in a number of applications such as, clarification and better understanding of their semantics and inter relations , query transformations, more precise query formulation, etc. We apply a procedure to create a graph of the Access Points, according to their subset relationship, based on the official semantics of(More)
Unsupported Z39.50 access points result to query failures and/or inconsistent answers, in spite of the protocol specification for a unified global access mechanism. A challenge to this issue is to substitute an unsupported access point with others, so that the most similar semantics to the original access point can be obtained. In this paper, we describe(More)
The digital library evaluation field has an evolving nature and it is characterized by a noteworthy proclivity to enfold various methodological orientations. Given the fact that the scientific literature in the specific domain is vast, researchers require tools that will exhibit either commonly acceptable practices, or areas for further investigation. In(More)
We evaluate the usage of a Digital Library with many different collections, by examining its log files, and we concluded that the access points that the users mostly refer to, depend heavily on the type of content of the collection. We also found that most users not only tend to use simple query structures (e.g. one search term) and very few operations per(More)