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Since its standardization by the World Wide Web Consortium (W3C) in 1998, the XML (acronym for eXtensible Markup Language) has been acknowledged as the de-facto standard format for data, besides being a data format employed by a wide and increasing number of application domains. XML allows data and textual contents to be structured; the structural elements are specified in plain text using strings of characters that can be easily read by computer programs, while maintaining human-readability. XPath and XQuery represent the two main standard languages that have been defined to inquire XML data; the two languages allow to select a subset of elements from an XML document, and to further manipulate its contents and to restructure the document tree form. Both XPath and XQuery are based on a Database perspective of XML documents, where the evaluation of the query clauses is performed like in the database query language SQL, from which both the XML languages took inspiration. The data-centric perspective adopted by the XQuery and XPath languages has been recently extended by an Information Retrieval oriented approach, where a new set of content-based constraints have been defined that allow a full-text search in an IR-style, with an element relevance scoring computation. This extension is called XQuery/XPath Full-Text and has been standardized by the W3C. In the Information Retrieval community other approaches have appeared that take into account the document structure and propose a set of approximate structural matching techniques, where the standard XQuery and XPath structural constraints are evaluated by path relaxation algorithms. Such approaches, however, do not offer the user the possibility to express vague structural constraints the approximate evaluation of which produces a set of weighted fragments, where the weight express the relevance of the fragment with respect to the structural constraints. This thesis describes the definition and the implementation of a fo

This paper presents the KBMS 2.0 Project, a system that is aimed at managing and searching information effectively. The idea is to leverage the information stored in any enterprise to support users during their interactions with the defined portal. The advanced portal has been developed to help users in finding information related to their information needs with the use of a friendly user interface. This task has been done by considering two key aspects: (1) context, and (2) personalization, respectively. Contextual information allows to filter out knowledge not related to users, whereas personalization aspects have been used to support users during their searches by considering user preferences and user activities.

Patent retrieval is a complex challenging task; despite of the numerous patent search applications, more flexible solutions are needed to help users to easily identify relevant patents. This paper presents the PatentLight search tool that offers novel and flexible functionalities to help users looking for relevant patents represented in the XML format. Copyright © 2012 ACM.

This paper presents a formal definition of an extension of the XQuery Full-Text language: the proposed extension consists in adding two new flexible axes, named below and near, which express structural constraints that can be specified by the user. Both constraints are evaluated in an approximate way with respect to a considered path, and their evaluation produces a path relevance score for each retrieved element. The formal syntax and the semantics of the two new axis are presented and discussed.

In this work we describe and evaluate an efficient data structure developed to deal with an extension of the XPath language that allows the specification of flexible constraints on both the textual content and the document structure of XML documents. Our approach is based on an inverted file representation of XML documents where both structure and content are taken into account. The proposed approach is described, as well as its implementation, by particularly addressing the problem of offering an efficient evaluation of structure-based flexible constraints

Service contracts represent the agreement between the service provider and potential service consumers to use a specific service under given conditions; for each service multiple service contracts are available. In this paper we investigate a new approach to support the service contract selection by exploiting preferences both explicitly defined by a user and implicitly inferred from his/her context. The core of our approach is the use of multi-constraint queries expressed on punctual values and on textual descriptions. Both semantic-based and information retrieval (IR) techniques are applied. Experimental evaluations show the effectiveness of the proposed approach

This paper presents an advanced indexing structure for XML documents which allows the evaluation of loose constraints on both structure and content of XML documents. This structure is an extension of the one presented in [1], and allows an evaluation of flexible queries performed into two subsequent steps: content-based matching and structure-based matching (applied to documents pre-selected by the first evaluation phase)