Web metadata is crucial for providing machine-understandable descriptions of Web resources, and has a number of applications such as discovery, qualification, and adaptation of Web documents. While annotations are often embedded into a Web document, annotations can also be associated externally by means of addressing expressions represented with the XPath language. However, there has been littl...

XPath, CTL and the modal logics proposed by Blackburn et al, Palm and Kracht are variable free formalisms to describe and reason about (finite) trees. XPath expressions evaluated at the root of a tree correspond to existential positive modal formulas. The models of XPath expressions are finite ordered trees, or in the presence of XML’s ID/IDREF mechanism graphs. The ID/IDREF mechanism can be se...

The syntactic wellformedness constraints of XML (opening and closing tags nest properly) imply that XML processors face the challenge to efficiently handle data that takes the shape of ordered, unranked trees. Although RDBMSs have originally been designed to manage table-shaped data, we propose their use as XML and XPath processors. In our setup, the database system employs a relational XML doc...

The XPath accelerator (“pre/post numbering”) has proven to be an efficient encoding to losslessly store XML data in relational databases. Conventional RDBMSs, however, remain ignorant of interesting properties of the encoded tree data, and make thus no or poor use of these properties. At VLDB 2003 we devised a new join algorithm, staircase join, that encapsulates tree-specific knowledge and can...

The core technical issue in XML message brokers, which play a key role in exchanging information in ubiquitous environments, is processing a large set of continuous XPath queries over incoming XML streams. In this paper, a new system as an epochal solution for this issue is proposed. The system is designed to minimize the runtime workload of continuous query processing by transforming XPath exp...

Geography Markup Language (GML) has been established as the standard language for the transport, storage and modelling of geographic information. In this paper we study how to adapt the XPath query language to GML documents. With this aim, we have defined a semantic based XPath language which is not based on the (tree-based) syntactic structure of GML documents, instead it is based on the “sema...

XPathLog is a logic-based language for manipulating and integrating XML data. It extends the XPath query language with Prolog-style variables. Due to the close relationship with XPath, the semantics of rules is easy to grasp. XPathLog defines a semantics for XPath expressions in rule heads, declaratively specifying how to create and update XML trees and nodes. In this paper, we show how XPathLo...

XPath is a language for selecting sequences of nodes and computing values from XML document trees; speci cally XPath can express navigation in an XML document. A peculiarity of the XPath semantics is that every expression is de ned in terms of not just the current context node in the tree but also the context position and context size that depend on the sequence from which the current node was ...

To properly encode properties of textual documents using XML, mul­ tiple markup hierarchies must be used, often leading to conflicting markup in encodings. Text Encoding Initiative (TEI) Guidelines[1] recognize this problem and suggest a number of ways to incorporate multiple hierarchies in a single well-formed XML document. In this paper, we present a framework for pro­ cessing XPath queries o...

Heterogeneous graph neural networks (HGNs) are prominent approaches to node classification tasks on heterogeneous graphs. Despite the superior performance, insights about predictions made from HGNs obscure humans. Existing explainability techniques mainly proposed for GNNs homogeneous They focus highlighting salient objects whereas problem of how these affect remains unsolved. Given graphs with...