Browsing Conference papers by Author "Arampatzis, Avi"

Now showing items 1-13 of 13

  • Accelerating Image Retrieval Using Binary Haar Wavelet Transform on the Color and Edge Directivity Descriptor 

    Chatzichristofis, Savvas A.; Boutalis, Yiannis; Arampatzis, Avi (Institute of Electrical and Electronics Engineers (IEEE), United States, 2010)
    In this paper, a new accelerating technique for content-based image retrieval is proposed, suitable for the Color and Edge Directivity Descriptor (CEDD). To date, the experimental results presented in the literature ...

  • Bag-of-visual-words vs global image descriptors on two-stage multimodal retrieval 

    Zagoris, Konstantinos; Chatzichristofis, Savvas A.; Arampatzis, Avi (ACM SIGIR 2011, 2011)
    The Bag-Of-Visual-Words (BOVW) paradigm is fast becoming a popular image representation for Content-Based Image Retrieval (CBIR), mainly because of its better retrieval effectiveness over global feature representations ...

  • DUTH at TREC 2013 Contextual Suggestion Track 

    Drosatos, George; Stamatelatos, Giorgos; Arampatzis, Avi; Efraimidis, Pavlos S. (2013)
    In this report we give an overview of our participation in the TREC 2013 Contextual Suggestion Track. We present an approach for context processing that comprises a newly designed and fine-tuned POI (Point Of Interest) ...

  • DUTH at TREC 2015 Clinical Decision Support Track 

    Drosatos, George; Roumeliotis, Stefanos; Arampatzis, Avi; Kaldoudi, Eleni (2015)
    In this report we give an overview of our participation in the TREC 2015 Clinical Decision Support Track. We present two approaches for pre-processing and indexing of the open-access PubMed articles, and four methods for ...

  • Dynamic Two-Stage Image Retrieval from Large Multimodal Databases 

    Arampatzis, Avi; Zagoris, Konstantinos; Chatzichristofis, Savvas A. (Springer-Verlag, 2011)
    Content-based image retrieval (CBIR) with global features is notoriously noisy, especially for image queries with low percentages of relevant images in a collection. Moreover, CBIR typically ranks the whole collection, ...

  • Enhancing Deniability against Query-Logs 

    Arampatzis, Avi; Efraimidis, Pavlos S.; Drosatos, George (Springer, 2011)
    We propose a method for search privacy on the Internet, focusing onenhancing plausible deniability against search engine query-logs. The method ap-proximates the target search results, without submitting the intended query ...

  • Fusion vs. Two-Stage for Multimodal Retrieval 

    Arampatzis, Avi; Zagoris, Konstantinos; Chatzichristofis, Savvas A. (Springer, 2011)
    We compare two methods for retrieval from multimodal collections. The first is a score-based fusion of results, retrieved visually and textually. The second is a two-stage method that visually re-ranks the top-K results ...

  • Late fusion of compact composite descriptors for retrieval from heterogeneous image databases 

    Chatzichristofis, Savvas A.; Arampatzis, Avi (Association for Computing Machinery (ACM), United States, 2010)
    Compact composite descriptors (CCDs) are global image features, capturing more than one types of information at the same time in a very compact representation. Their quality has so far been evaluated in retrieval from ...

  • Multimedia Search with Noisy Modalities: Fusion and Multistage Retrieval 

    Arampatzis, Avi; Chatzichristofis, Savvas A.; Zagoris, Konstantinos (ImageClef, Wikipedia Retrieval Task, 2010)
    We report our experiences from participating to the controlled experiment of the ImageCLEF 2010 Wikipedia Retrieval task. We built an experimental search engine which combines multilingual and multi-image search, employing ...

  • Pythia: A Privacy-enhanced Personalized Contextual Suggestion System for Tourism 

    Drosatos, George; Efraimidis, Pavlos S.; Arampatzis, Avi; Stamatelatos, Giorgos; Athanasiadis, Ioannis N. (COMPSAC, 2015-07)
    We present Pythia, a privacy-enhanced non-invasive contextual suggestion system for tourists, with important architectural innovations. The system offers high quality personalized recommendations, non-invasive operation ...

  • The TREC files: the (ground) truth is out there 

    Chatzichristofis, Savvas A.; Zagoris, Konstantinos; Arampatzis, Avi (Association for Computing Machinery (ACM), United States, 2011)
    Traditional tools for information retrieval (IR) evaluation, such as TREC’s trec_eval, have outdated command-line interfaces with many unused features, or ‘switches’, accumulated over the years. They are usually seen ...

  • A Versatile Tool for Privacy-Enhanced Web Search 

    Arampatzis, Avi; Drosatos, George; Efraimidis, Pavlos S. (European Conference on Information Retrieval, 2013)
    We consider the problem of privacy leaks suffered by Internet users when they perform web searches, and propose a framework to mitigate them. Our approach, which builds upon and improves recent work on search privacy, ...

  • www.MMRetrieval.net: a multimodal search engine 

    Zagoris, Konstantinos; Chatzichristofis, Savvas A.; Arampatzis, Avi (Association for Computing Machinery (ACM), United States, 2010)
    We introduce an experimental search engine for multilin- gual and multimedia information, employing a holistic web interface and enabling the use of highly distributed indices. Modalities are searched in parallel, and ...