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Giannopoulos G.,IMIS Institute | Koniaris M.,National Technical University of Athens | Weber I.,Qatar Computing Research Institute | Jaimes A.,Yahoo! Research | Sellis T.,RMIT University
Journal of Intelligent Information Systems | Year: 2014

In this paper, we introduce an approach for diversifying user comments on news articles. We claim that, although content diversity suffices for the keyword search setting, as proven by existing work on search result diversification, it is not enough when it comes to diversifying comments of news articles. Thus, in our proposed framework, we define comment-specific diversification criteria in order to extract the respective diversification dimensions in the form of feature vectors. These criteria involve content similarity, sentiment expressed within comments, named entities, quality of comments and combinations of them. Then, we apply diversification on comments, utilizing the extracted features vectors. The outcome of this process is a subset of the initial set that contains heterogeneous comments, representing different aspects of the news article, different sentiments expressed, different writing quality, etc. We perform an experimental analysis showing that the diversity criteria we introduce result in distinctively diverse subsets of comments, as opposed to the baseline of diversifying comments only w.r.t. to their content. We also present a prototype system that implements our diversification framework on news articles comments. © 2014, Springer Science+Business Media New York.

Makris K.,Technical University of Crete | Bikakis N.,National Technical University of Athens | Bikakis N.,IMIS Institute | Gioldasis N.,Technical University of Crete | Christodoulakis S.,Technical University of Crete
ACM International Conference Proceeding Series | Year: 2012

The Web of Data is an open environment consisting of very large, inter-linked RDF datasets from various domains (e.g., DBpedia, GeoNames, ACM, PubMed, etc.) accessed through SPARQL queries. Establishing interoperability in this environment has become a major research challenge. This paper presents Sparql - Rw (SPARQL - ReWriting), a framework which provides transparent query access over mapped RDF datasets. The Sparql - Rw provides a generic method for SPARQL query rewriting, with respect to a set of predefined mappings between ontology schemas. To this end, it supports a set of rich and flexible mapping types and it is proved to provide semantics preserving queries. © 2012 Authors.

Westerski A.,Technical University of Madrid | Dalamagas T.,IMIS Institute | Iglesias C.A.,Technical University of Madrid
Decision Support Systems | Year: 2013

The Idea Management Systems are a tool for collecting ideas for innovation from large communities. One of the problems of those systems is the difficulty to accurately depict the distinctive features of ideas in a rapid manner and use them for judgement of proposed innovations. Our research aims to solve this problem by introducing annotation of ideas with a domain independent taxonomy that describes various characteristics of ideas. The findings of our study show that such annotations can be successfully transformed into new metrics that allow the comparison of ideas with similar successfulness as the metrics already used in Idea Management Systems but in greater detail. The presented results are based on experiments with over 50,000 ideas gathered from case studies of four different organisations: Dell, Starbucks, Cisco and Canonical. © 2012 Elsevier B.V.

Paraskevopoulou M.D.,Biomedical science Research Center Alexander Fleming | Paraskevopoulou M.D.,National and Kapodistrian University of Athens | Georgakilas G.,Biomedical science Research Center Alexander Fleming | Georgakilas G.,University of Thessaly | And 9 more authors.
Nucleic Acids Research | Year: 2013

Recently, the attention of the research community has been focused on long non-coding RNAs (IncRNAs) and their physiological/pathological implications. As the number of experiments increase in a rapid rate and transcriptional units are better annotated, databases indexing IncRNA properties and function gradually become essential tools to this process. Aim of DIANA-LncBase (www. microrna.gr/LncBase) is to reinforce researchers' attempts and unravel microRNA (miRNA)-IncRNA putative functional interactions. This study provides, for the first time, a comprehensive annotation of miRNA targets on IncRNAs. DIANA-LncBase hosts transcriptome-wide experimentally verified and computationally predicted miRNA recognition elements (MREs) on human and mouse IncRNAs. The analysis performed includes an integration of most of the available IncRNA resources, relevant high-throughput HITS-CLIP and PAR-CLIP experimental data as well as state-of-the-art in silico target predictions. The experimentally supported entries available in DIANA-LncBase correspond to >5000 interactions, while the computationally predicted interactions exceed 10 million. DIANA-LncBase hosts detailed information for each miRNA-IncRNA pair, such as external links, graphic plots of transcripts' genomic location, representation of the binding sites, IncRNA tissue expression as well as MREs conservation and prediction scores. © The Author(s) 2012.

Giannopoulos G.,IMIS Institute | Sellis T.,RMIT University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2014

Microblogs have become an important source of information, a medium for following and spreading trends, news and ideas all over the world. As a result, microblog search has emerged as a new option for covering user information needs, especially with respect to timely events, news or trends. However users are frequently overloaded by the high rate of produced microblogging posts, which often carry no new information with respect to other similar posts. In this paper we propose a method that helps users effectively harvest information from a microblogging stream, by filtering out redundant data and maximizing diversity among the displayed information. We introduce microblog posts-specific diversification criteria and apply them on heuristic diversification algorithms. We implement the above methods into a prototype system that works with data from Twitter. The experimental evaluation, demonstrates the effectiveness of applying our problem specific diversification criteria, as opposed to applying plain content diversity on microblog posts. © Springer International Publishing Switzerland 2014.

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