Ontogator — A Semantic View-Based Search Engine Service for Web Applications

Abstract

Abstract. View-based search provides a promising paradigm for formulating complex semantic queries and representing results on the Semantic Web. A challenge for the application of the paradigm is the complexity of providing view-based search services through application programming interfaces (API) and web services. This paper presents a solution on how semantic view-based search can be provided efficiently through an API or as web service to external applications. The approach has been implemented as the open source tool Ontogator, that has been applied successfully in several practical semantic portals on the web. Keywords: semantic view-based search, view projection, Semantic Web middleware Interfacing Search ServicesThe Semantic Web enables querying data based on various combinations of semantic relationships. Because of the RDF data model, these queries are usually drafted as possibly complex sets of semantic relation patterns. An example would be "Find all toys manufactured in Europe in the 19th century, used by someone born in the 20th century". Here "toys", "Europe", "the 18th century", "someone" and "the 19th century" are ontological class restrictions on nodes and "manufactured in", "used by" and "time of birth" are the required connecting arcs in the pattern. While such queries are easy to formalize and query as graph patterns, they remain problematic because they are not easy for users to formulate. Therefore, much of the research in complex semantic queries has been on user interfaces [1,2] for creating complex query patterns as intuitively as possible.View-based search [3,4] is a search interface paradigm based on a longrunning library tradition of faceted classification [5]. Usability studies done on view-based search systems, such as Flamenco [6,4] and Relation Browser++ [7] have proved the paradigm both powerful and intuitive for end-users, particularly in drafting complex queries. Thus, view-based search presents a promising

Combining Faceted Search and Query Languages for the Semantic Web

“…They all have in common to assume that data is represented in a SW format, either RDF(S) or OWL. Most of them, such as Ontogator [MHS06], mSpace 6 , and Longwell 7 , do not claim for a contribution in terms of expressiveness, and contribute either to the design of better interfaces and visualizations, or to methods for the rapid or user-centric configuration of faceted views [SVH07]. Therefore, their contributions are somewhat orthogonal to ours, and could certainly complement ours.…”

Exploratory Web Searching with Dynamic Taxonomies and Results Clustering

“…[16]), Semantic Web (e.g. [9,15]), general purpose WSEs (e.g. Google Base), and other frameworks (e.g.…”

“…Related Work Systems like [24,9,13,15,2] support multiple facets, each associated with a taxonomy which can be predefined. Moreover, the systems described in [24,9,15] support ways to configure the taxonomies that are available during browsing based on the contents of the results.…”

“…Moreover, the systems described in [24,9,15] support ways to configure the taxonomies that are available during browsing based on the contents of the results. Specifically, [24] enriches the values of the object descriptions with more broad terms by exploiting WordNet, [9] supports rules for deciding which facets should be used according to the type of data objects based on RDF, and [15] supports reclassification of the objects to predefined types. However, none of these systems apply content-based results clustering, re-constructing the cluster tree taxonomy while the user explores the answer set.…”

FlexIR: a Domain-Specific Information Retrieval System

“…The research devoted to the concept of dimensions is mainly related to the development of tools for navigating through document collections. These tools are based on the paradigm of research known as faceted search [1][2] [3] or view-based search [4] [5].…”