Carlos A. Heuser

From XML view updates to relational view updates: old solutions to a new problem

This paper addresses the question of updating relational databases through XML views. Using query trees to capture the notions of selection, projection, nesting, grouping, and heterogeneous sets found throughout most XML query languages, we show how XML views expressed using query trees can be mapped to a set of corresponding relational views. We then show how updates on the XML view are mapped to updates on the corresponding relational views. Existing work on updating relational views can then be leveraged to determine whether or not the relational views are updatable with respect to the relational updates, and if so, to translate the updates to the underlying relational database.

A Rule-Based Conversion of a DTD to a Conceptual Schema

XML is a common standard for semi-structured and structured data representation and exchange over the Web. This paper describes a semi-automatic process for converting an XML DTD to a schema in a canonical conceptual model based on ORM/NIAM and extended ER models. This process is part of a bottom-up approach for integration of XML sources that takes a set of DTDs and generates an ontology for query purposes. Ac onceptual schema for a DTD simplifies the integration activity because provides a semantically rich representation of an XML source. The core of the process is a set of conversion rules that consider the DTD structure and heuristics related to default semantic interpretations on such structure in order to generate the corresponding concepts in the canonical conceptual schema.

Measuring quality of similarity functions in approximate data matching

This paper presents a method for assessing the quality of similarity functions. The scenario taken into account is that of approximate data matching, in which it is necessary to determine whether two data instances represent the same real world object. Our method is based on the semi-automatic estimation of optimal threshold values. We propose two methods for performing such estimation. The first method is an algorithm based on a reward function, and the second is a statistical method. Experiments were carried out to validate the techniques proposed. The results show that both methods for threshold estimation produce similar results. The output of such methods was used to design a grading function for similarity functions. This grading function, called discernability, was used to compare a number of similarity functions applied to an experimental data set.

Querying Heterogeneous XML Sources through a Conceptual Schema

XML is a widespread W3C standard used by several kinds of applications for data representation and exchange over the web. In the context of a system that provides semantic integration of heterogeneous XML sources, the same information at a semantic level may have different representations in XML. However, the syntax of an XML query depends on the structure of the specific XML source. Therefore, in order to obtain the same query result, one must write a specific query for each XML source. To deal with such problem, a much better solution is to state queries against a global conceptual schema and then translate them into an XML query against each specific data source. This paper presents CXPath (Conceptual XPath), a language for querying XML sources at the conceptual level, as well as a translation mechanism that converts a CXPath query to an XPath query against a specific XML source.

Advances in Conceptual Modeling - Challenging Perspectives

CoMoL 2009 - Conceptual Modeling in the Large.- Preface to CoMoL 2009.- Semantic Service Design for Collaborative Business Processes in Internetworked Enterprises.- Algebraic Meta-structure Handling of Huge Database Schemata.- On Computing the Importance of Entity Types in Large Conceptual Schemas.- ETheCoM 2009 - First International Workshop on Evolving Theories of Conceptual Modelling.- Preface to ETheCoM 2009.- Invited Talks.- Is It Important to Explain a Theorem? A Case Study on UML and .- Towards a Theory of Conceptual Modelling.- Accepted Papers.- Assessing Modal Aspects of OntoUML Conceptual Models in Alloy.- First-Order Types and Redundant Relations in Relational Databases.- On Matrix Representations of Participation Constraints.- Toward Formal Semantics for Data and Schema Evolution in Data Stream Management Systems.- XML Machines.- FP-UML 2009 - Fifth International Workshop on Foundations and Practices of UML.- Preface to FP-UML 2009.- Dependability and Agent Modeling.- Applying AUML and UML 2 in the Multi-agent Systems Project.- A Collaborative Support Approach on UML Sequence Diagrams for Aspect-Oriented Software.- Applying a UML Extension to Build Use Cases Diagrams in a Secure Mobile Grid Application.- Semantics Representation and Tools.- The MP (Materialization Pattern) Model for Representing Math Educational Standards.- XMI2USE: A Tool for Transforming XMI to USE Specifications.- MOST-ONISW 2009 - The Joint International Workshop on Metamodels, Ontologies, Semantic Technologies, and Information Systems for the Semantic Web.- Preface to MOST-ONISW 2009.- Analysis Procedure for Validation of Domain Class Diagrams Based on Ontological Analysis.- Ontology for Imagistic Domains: Combining Textual and Pictorial Primitives.- Using a Foundational Ontology for Reengineering a Software Enterprise Ontology.- Multi-level Conceptual Modeling and OWL.- QoIS 2009 - The Fourth International Workshop on Quality of Information Systems.- Preface to QoIS 2009.- Assessment of Data Quality Factors.- Completeness in Databases with Maybe-Tuples.- Modeling, Measuring and Monitoring the Quality of Information.- Tools for Information System Quality Assessment.- Evaluating the Functionality of Conceptual Models.- Qbox-Services: Towards a Service-Oriented Quality Platform.- RIGiM 2009 - Third International Workshop on Requirements, Intentions and Goals in Conceptual Modeling.- Preface to RIGiM 2009.- Modelling.- A Comparison of Goal-Oriented Approaches to Model Software Product Lines Variability.- A Lightweight GRL Profile for i* Modeling.- Elicitation Issues.- From User Goals to Service Discovery and Composition.- ITGIM: An Intention-Driven Approach for Analyzing the IT Governance Requirements.- Adapting the i* Framework for Software Product Lines.- SECOGIS 2009 - Third International Workshop on Semantic and Conceptual Issues in Geographic Information Systems.- Preface to SeCoGIS 2009.- Foundational Aspects.- A New Point Access Method Based on Wavelet Trees.- A Reference System for Topological Relations between Compound Spatial Objects.- A Model for Geographic Knowledge Extraction on Web Documents.- Semantical Aspects.- A Semantic Approach to Describe Geospatial Resources.- An Ontology-Based Framework for Geographic Data Integration.- A Semantic Approach for the Modeling of Trajectories in Space and Time.

Measuring similarity between collection of values

In this paper, we propose a set of similarity metrics for manipulating collections of values occuring in XML documents. Following the data model presented in TAX algebra, we treat an XML element as a labeled ordered rooted tree. Consider that XML nodes can be either atomic, i.e, they may contain single values such as short character strings, date, etc, or complex, i.e., nested structures that contain other nodes, we propose two types of similarity metrics: MAVs, for atomic nodes and MCVs, for complex nodes. In the first case, we suggest the use of several application domain dependent metrics. In the second case, we define metrics for complex values that are structure dependent, and can be distinctly applied for it and collections of values. We also present experiments showing the effectiveness of our method.

PATAXÓ: A framework to allow updates through XML views

XML has become an important medium for data exchange, and is frequently used as an interface to (i.e., a view of) a relational database. Although a lot of work has been done on querying relational databases through XML views, the problem of updating relational databases through XML views has not received much attention. In this work, we map XML views expressed using a subset of XQuery to a corresponding set of relational views. Thus, we transform the problem of updating relational databases through XML views into a classical problem of updating relational databases through relational views. We then show how updates on the XML view are mapped to updates on the corresponding relational views. Existing work on updating relational views can then be leveraged to determine whether or not the relational views are updatable with respect to the relational updates, and if so, to translate the updates to the underlying relational database.

A method for the unification of XML schemata

Abstract Extensible Markup Language (XML) is a common standard for data representation and exchange over the Web. Considering the increasing need for managing data on the Web, integration techniques are required to access heterogeneous XML sources. In this paper, we describe a unification method for heterogeneous XML schemata. The input to the unification method is a set of object-oriented-based canonical schemata that conceptually abstract local Document Type Definitions of the involved sources. The unification process applies specific algorithms and rules to the concepts of the canonical schemata to generate a preliminary ontology . Further adjustments on this preliminary ontology generate a reference ontology that acts as a front-end for user queries to the XML sources.

Estimating recall and precision for vague queries in databases

In vague queries, a user enters a value that represents some real world object and expects as the result the set of database values that represent this real world object even with not exact matching. The problem appears in databases that collect data from different sources or databases were different users enter data directly. Query engines usually rely on the use of some type of similarity metric to support data with inexact matching. The problem of building query engines to execute vague queries has been already studied, but an important problem still remains open, namely that of defining the threshold to be used when a similarity scan is performed over a database column. From the bibliography it is known that the threshold depends on the similarity metrics and also on the set of values being queried. Thus, it is unrealistic to expect that the user supplies a threshold at query time. In this paper we propose a process for estimation of recall/precision values for several thresholds for a database column. The idea is that this process is started by a database administrator in a pre-processing phase using samples extracted from database. The meta-data collected by this process may be used in query processing in the optimization phase. The paper describes this process as well as experiments that were performed in order to evaluate it.

Matching XML documents in highly dynamic applications

Highly dynamic applications like the Web and peer-to-peer systems require a great deal of effort in document management. Documents from different sources may contain parts that, although having different structure or different contents, may be considered as representing the same conceptual information. One essential task in this scenario is the identification of complementary or overlapping documents that need to be integrated. In this paper, we deal specifically with documents represented in the XML format. XML document integration is an important process in highly dynamic applications, for the volume of data available in this format is constantly growing. XML integration is also a challenging task, due to the flexible nature of XML, which may lead to structure divergences and content conflicts between the documents. In this work, we present a novel approach to the matching problem, i.e., the problem of defining which parts of two documents contain the same information. Matching is usually the first step of an integration process. Our approach is novel in the sense it combines similarity information from the content of the elements with information from the structure of the documents. This feature, as our experiments confirm, makes our approach capable of dealing with content as well as structural divergences.