fragments. Another common database model — graph databases — also requires a heavy use of navigation in queries; yet it largely adopts a different approach to querying, relying on reachability patterns expressed with regular constraints. Our goal here is to investigate the behavior and applicability

Graph data appears in a variety of application domains, and many uses of it, such as querying, matching, and transforming data, naturally result in incompletely specified graph data, i.e., graph patterns. While queries need to be posed against such data, techniques for querying patterns

Query graphs with cuts are inspired by Sowa’s conceptual graphs, which are in turn based on Peirce’s existential graphs. In my thesis ‘The Logic System of Concept Graphs with Negations’, conceptual graphs are elaborated mathematically, and the cuts of existential graphs are added to them

In many applications the available data give rise to an attributed graph, with the nodes corresponding to the entities of interest, edges to their relationships and attributes on both provide additional characteristics. To mine such data structures we have proposed a visual analytic algebra

committee, Professor Hosagrahar V. Jagadish, Professor Farnam Jahanian and Professor David J. States, for their time and effort to help improve and refine my thesis. In particular, Professor States provided me with the BioNLP dataset for the approximate graph matching experiments and helped me develop

We study a spatial logic for reasoning about labelled directed graphs, and the application of this logic to provide a query language for analysing and manipulating such graphs. We give a graph description using constructs from process algebra. We introduce a spatial logic in order to reason

Pipelining is a widely used technique that query execution engines employ to improve individual query execution times. In recently proposed settings, pipelining is used as an alternative to materialization to evaluate query plan graphs, where nodes in a query plan can have multiple parents

This paper presents G²QL, a language to query graph structures that was designed as a supplement to an overall approach to graph based software development. G²QL allows users to specify graph patterns graphically. Complex conditions can be expressed textually, using a predicate language called

We propose a data model and query language that integrates an explicit modeling and querying of graphs smoothly into a standard database environment. For standard applications, some key features of object-oriented modeling are offered such as object classes organized into a hierarchy, object

RDF repositories provide query capabilities, some of them require manual interaction to reduce query execution time by several orders of magnitude. In this paper, we propose the SPARQL query graph model (SQGM) supporting all phases of query processing. On top of the SQGM we defined transformations