Mirian Halfeld Ferrari

Incremental Constraint Checking for XML Documents

We introduce a method for building an XML constraint validator from a given set of schema, key and foreign key constraints. The XML constraint validator obtained by our method is a bottom-up tree transducer that is used not only for checking, in only one pass, the correctness of an XML document but also for incrementally validating updates over this document. In this way, both the verification from scratch and the update verification are based on regular (finite and tree) automata, making the whole process efficient.

PEWS platform: a web services composition environment

PEWS (Predicate Path Expression for Web Services) is a programming language for the definition of web service behavioral interfaces. PEWS programs can be used for the description of both simple and composite web services. Simple web services can be built from scratch, by the combination of operations defined in a WSDL description file. Composite web services are constructed from the combination of existing web services, accessed by using their WSDL descriptions. PEWS operators help to define the order in which web services and operations will be performed. This paper presents a PEWS programs edition environment. This environment is in the form of a web interface that enables programmers to edit, test and run composition specifications. The front-end of the environment, i.e. the web interface, interacts with the back-end, a server-side application, for the specification analysis. Our platform offers the possibility of an automatic translation of a PEWS specification into a Java program skeleton, directly executable, to call the web service operations and perform them in the order defined by the PEWS specification. Thus, the use of this platform can help reducing the time for development of the compositions

Composing Web Services with PEWS: A Trace-Theoretical Approach

PEWS is an interface description language for both individual and composed Web services. Individual Web services are expressions over WSDL-defined operations while composed Web services are expressions over PEWS-defined services. This paper distinguishes two dimensions of PEWS. The control dimension describes the control workflow of the service, i.e. the order in which the operations of the Web service will be executed. No data constraints are imposed. The data dimension adds information flow to the control dimension. In order to analyse the composability and the substitutability of composed services, we introduce a trace-theoretical presentation of the language constructs. Our long-term goal is to integrate PEWS into a Web service design system that checks useful properties of the service specification

Regular expression transformations to extend regular languages (with application to a Datalog XML schema validator)

An XML schema is a set of rules for defining the allowed sub-elements of any element in an XML document. These rules use regular expressions to define the language of the elements children. Updates to an XML schema are updates to the regular expressions defined by the schema rules. We consider an interactive, data administration tool for XML databases. In this tool, changes on an XML schema are activated by updates that violate the validity of an XML document. Our schema validator is a Datalog program, resulting from the translation of a given XML schema. Changing the schema implies changing the validator. The main contribution of this paper is an algorithm allowing the evolution of XML schemas. This algorithm is based on the computation of new regular expressions to extend a given regular language in a conservative way, trying to foresee the needs of an application. A translation function from schema constraints to Datalog programs is introduced. The validation of an XML tree corresponds to the evaluation of the Datalog program over the tree. Our method allows the maintenance of the Datalog program in an incremental way, i.e., without redoing the entire translation.

Attribute grammar for XML integrity constraint validation

The main contribution of this paper is a generic grammarware for validating XML integrity constraints. Indeed, we use an attribute grammar to describe XML documents and constraints. We thus explain the main parts of this novel algorithm and we report on experiments showing that our method allows for an effective and efficient validation of XML functional dependencies (XFD).

Contraintes d'intégrité pour XML. Visite guidée par une syntaxe homogène

The XML format is used to represent real-world data, which must respect certain integrity constraints. These constraints are defined to ensure accuracy and consistency of data. Within the framework of relational databases, integrity constraints have been extensively studied and since the beginning of 2000 s, their XML equivalents are explored by several researches, which focused their attention on a type or another of constraint. This article aims to be a survey on XML integrity constraints by providing a homogeneous formalism and by clarifying the semantics of each type of constraint.

Conservative type extensions for XML data

We introduce a method for building a minimal XML type (belonging to standard class of regular tree grammars) as an extension of other given types. Not only do we propose an easy-to-handle XML type evolution method, but we prove that this method computes the smallest extension of a given tree grammar, respecting pre-established constraints. We also adapt our technique to an interactive context, where an advised user is guided to build a new XML type from existing ones. A basic prototype of our tool is implemented.

Automatic refinement of service compositions

We propose a method for the automatic refinement of web service compositions: given a composite web service specification over abstract modules, our method generates lower-level versions of this composition. The refinement process is based on query rewriting techniques extended to take into account not only functional and non-functional requirements but also semantic information. Experimental results illustrate the performance and scalability of the method.

Dependence graphs for verifications of web service compositions with PEWS

PEWS is an interface description language for both individual and composed web services. We propose an approach for verifying PEWS compositions which exploits dependence graphs (equivalent to trace systems). The introduction of a synchronization based on dependence graphs allows more efficient algorithms for testing composition properties.

Experiments on service composition refinement on the basis of preference-driven recommendation

The service oriented computing paradigm proposes the construction of applications by integrating pre-existent services. Since a large number of services may be available in the cloud, service recommendation and selection are key problems. The paper proposes the automation of the selection task that takes the abstract specification of a composition, the definition of concrete services and the preferences obtained from a recommendation routine to produce a list of refinements in preference order. This paper presents three versions of our approach. They differ in implementation options or in the methods used to combine preferences. Experiment results are provided as a benchmark for ensuring the efficiency of our proposal in practice.