Now showing items 574-593 of 1009

  • Natix: A technology overview 

    Fiebig, T; Helmer, S; Kanne, CC; Moerkotte, G; Neumann, J; Schiele, R; Westmann, T (Springer, 2002)
    Several alternatives to manage large XML document collections exist, ranging from file systems over relational or other database systems to specifically tailored XML base management systems. In this paper we review Natix, ...
  • Nearest-biclusters collaborative filtering with constant values 

    Symeonidis P; Nanopoulos A; Papadopoulos A; Manolopoulos Y (Springer, 2007)
    Collaborative Filtering (CF) Systems have been studied extensively for more than a decade to confront the "information overload" problem. Nearest-neighbor CF is based either on common user or item similarities, to form the ...
  • Nested logic programs with ordered disjunction 

    Confalonieri R; Nieves J (CEUR-WS, 2010)
    In this paper we define a class of nested logic programs, nested logic programs with ordered disjunction (LPODs+), which allows to specify qualitative preferences by means of nested preference expressions. For doing this ...
  • Nested queries and quantifiers in an ordered context 

    May, N; Helmer, S; Moerkotte, G (IEEE, 2004)
    We present algebraic equivalences that allow to unnest nested algebraic expressions for order-preserving algebraic operators. We illustrate how these equivalences can be applied successfully to unnest nested queries given ...
  • New perspectives for recommendations in location-based social networks: Time, privacy and explainability 

    Kefalas P; Symeonidis P; Manolopoulos Y (ACM, 2013)
    Online social networks have attracted users' attention in the last decade. Recommendation services constitute a critical functionality of such social platforms: users receive recommendations about resources (documents, ...
  • New Trends in Databases and Information Systems: Contributions from ADBIS 2017 Workshops 

    Behrend A; Calvanese D; Cerquitelli T; Chiusano S; Engels C; Jean S; Kozmina N; Markhoff B; Romero O; Vahdati S (Springer, 2017)
    In the last few years, research on database and information system technologies has been rapidly evolving thanks to the new paradigms of software and hardware adopted by modern scientific and more invasive applications. A ...
  • Node selection query languages for trees 

    Calvanese D; De Giacomo G; Lenzerini M; Vardi M (AAAI Publications, 2010)
    The study of node-selection query languages for (finite) trees has been a major topic in the recent research on query lan- guages for Web documents. On one hand, there has been an extensive study of XPath and its various ...
  • Non-Gödel Negation Makes Unwitnessed Consistency Undecidable 

    Borgwardt S; Peñaloza R (CEUR, 2012)
    Recent results show that ontology consistency is undecidable for a wide variety of fuzzy Description Logics (DLs). Most notably, undecidability arises for a family of inexpressive fuzzy DLs using only conjunction, existential ...
  • Non-invasive data acquisition for user modeling 

    Košir A; Tkalčič M; Tasič J ([s.n.], 2008)
    One of the most impending drawbacks of modern information technology and communication devices is the problem of user interfacing. The focus of the research community to tackle this problem is almost exclusively set to the ...
  • Novelty-Aware Matrix Factorization Based on Items’ Popularity 

    Coba L; Symeonidis P; Zanker M (Springer, 2018)
    The search for unfamiliar experiences and novelty is one of the main drivers behind all human activities, equally important with harm avoidance and reward dependence. A recommender system personalizes suggestions to ...
  • The NPD Benchmark for OBDA Systems 

    Lanti D; Rezk M; Slusnys M; Xiao G; Calvanese D (CEUR Electronic Workshop Proceedings, 2014)
    In Ontology-Based Data Access (OBDA), queries are posed over a high-level conceptual view, and then translated into queries over a potentially very large (usually relational) data source. The ontology is connected to the ...
  • The NPD benchmark: Reality check for OBDA systems 

    Lanti D; Rezk M; Xiao G; Calvanese D (OpenProceedings.org, 2015)
    In the last decades we moved from a world in which an enterprise had one central database - rather small for todays' standards - to a world in which many different - and big - databases must interact and operate, providing ...
  • The NPD Benchmark: Reality Check for OBDA Systems 

    Lanti, D; Rezk, M; Xiao, G; Calvanese, D (OpenProceedings.org, 2015)
    In the last decades we moved from a world in which an enterprise had one central database—rather small for todays’ standards—to a world in which many different—and big—databases must interact and operate, providing the ...
  • OBDA Beyond Relational DBs: A Study for MongoDB 

    Botoeva E; Calvanese D; Cogrel B; Rezk M; Xiao G (CEUR Workshop Proceedings, 2016)
    The database landscape has been significantly diversified during the last decade, resulting in the emergence of a variety of non-relational (also called NoSQL) databases, e.g., XML and JSON-document databases, key-value ...
  • OBDA for Log Extraction in Process Mining 

    Calvanese D; Kalayci TE; Montali M; Santoso A (Springer, 2017)
    Process mining is an emerging area that synergically combines model-based and data-oriented analysis techniques to obtain useful insights on how business processes are executed within an organization. Through process mining, ...
  • OBDA Over Non-Relational Databases 

    Botoeva E; Calvanese D; Cogrel B; Rezk M; Xiao G (CEUR Workshop Proceedings, 2016)
    The database landscape has been significantly diversified during the last decade, resulting in the emergence of a variety of non-relational (also called NoSQL) databases, e.g., XML and JSON-document databases, key-value ...
  • OBDA with the Ontop Framework 

    Calvanese D; Cogrel B; Guzel Kalayci E; Komla Ebri S; Kontchakov R; Lanti D; Rezk M; Rodriguez-Muro M; Xiao G (Curran, 2015)
    Ontology-based data access (OBDA) has become a popular paradigm for accessing data stored in legacy sources using Semantic Web technologies. In the OBDA setting, users access the data through a conceptual layer, which ...
  • Object-Centric Behavioral Constraints: Integrating Data and Declarative Process Modelling 

    Artale A; Montali M; Tritini S; van der Aalst WMP (CEUR-WS.org, 2017)
  • Observation and abstract behaviour in specification and implementation of state-based systems 

    Pahl C (British Computer Society, 2001)
    Classical algebraic specification is an accepted framework for specification. A criticism which applies is the fact that it is functional, not based on a notion of state as most software development and implementation ...
  • OCL-Lite: A decidable (yet expressive) fragment of OCL 

    Queralt A; Artale A; Calvanese D; Teniente E (CEUR-WS.org, 2012)
    UML has become a de facto standard in conceptual modeling. Class diagrams in UML allow one to model the data in the domain of interest by specifying a set of graphical constraints. However, in most cases one needs to provide ...