State-of-the-art on evolution and reactivity

This report starts by, in Chapter 1, outlining aspects of querying and updating resources on the Web and on the Semantic Web, including the development of query and update languages to be carried out within the Rewerse project. From this outline, it becomes clear that several existing research areas and topics are of interest for this work in Rewerse. In the remainder of this report we further present state of the art surveys in a selection of such areas and topics. More precisely: in Chapter 2 we give an overview of logics for reasoning about state change and updates; Chapter 3 is devoted to briefly describing existing update languages for the Web, and also for updating logic programs; in Chapter 4 event-condition-action rules, both in the context of active database systems and in the context of semistructured data, are surveyed; in Chapter 5 we give an overview of some relevant rule-based agents frameworks

Web and Semantic Web Query Languages

A number of techniques have been developed to facilitate powerful data retrieval on the Web and Semantic Web. Three categories of Web query languages can be distinguished, according to the format of the data they can retrieve: XML, RDF and Topic Maps. This article introduces the spectrum of languages falling into these categories and summarises their salient aspects. The languages are introduced using common sample data and query types. Key aspects of the query languages considered are stressed in a conclusion

Survey over Existing Query and Transformation Languages

A widely acknowledged obstacle for realizing the vision of the Semantic Web is the inability of many current Semantic Web approaches to cope with data available in such diverging representation formalisms as XML, RDF, or Topic Maps. A common query language is the first step to allow transparent access to data in any of these formats. To further the understanding of the requirements and approaches proposed for query languages in the conventional as well as the Semantic Web, this report surveys a large number of query languages for accessing XML, RDF, or Topic Maps. This is the first systematic survey to consider query languages from all these areas. From the detailed survey of these query languages, a common classification scheme is derived that is useful for understanding and differentiating languages within and among all three areas

State-of-the-art on evolution and reactivity

This report starts by, in Chapter 1, outlining aspects of querying and updating resources on the Web and on the Semantic Web, including the development of query and update languages to be carried out within the Rewerse project. From this outline, it becomes clear that several existing research areas and topics are of interest for this work in Rewerse. In the remainder of this report we further present state of the art surveys in a selection of such areas and topics. More precisely: in Chapter 2 we give an overview of logics for reasoning about state change and updates; Chapter 3 is devoted to briefly describing existing update languages for the Web, and also for updating logic programs; in Chapter 4 event-condition-action rules, both in the context of active database systems and in the context of semistructured data, are surveyed; in Chapter 5 we give an overview of some relevant rule-based agents frameworks

XFormsDB - An XForms-Based Framework for Simplifying Web Application Development

WWW:n luonne muuttuu jatkuvasti vastatakseen paremmin käyttäjien kasvavia tarpeita. Vaikka tämä kehitys kohti hyödyllisempiä vuorovaikutteisia palveluita ja sovelluksia on parantanut WWW:n käyttö- ja käyttäjäkokemusta, niin se on myös samalla tehnyt WWW-sovellusten kehittämisestä paljon monimutkaisempaa. Tämän työn päätavoitteena oli tutkia, miten WWW-sovellusten kehittämistä voitaisiin helpottaa deklaratiivisen ohjelmoinnin keinoin. Työssä esitetään laajennus, jonka avulla yleisimmät palvelinpään toiminnallisuudet voidaan saumattomasti liittää osaksi XForms-merkintäkieltä. Myös laajennuksen käyttökelpoisuus ja mahdollisuudet validoidaan prototyyppitoteutuksen, nimeltään XFormsDB-ohjelmistokehys, ja kahden WWW-esimerkkisovelluksen avulla. Tulokset osoittavat, että XFormsDB-ohjelmistokehyksen avulla voidaan kirjoittaa hyödyllisiä, erittäin vuorovaikutteisia monen käyttäjän WWW-sovelluksia nopeasti ja helposti vain yhtä dokumenttia ja yhtä ohjelmointimallia käyttäen.The nature of the World Wide Web is constantly changing to meet the increasing demands of its users. While this trend towards more useful interactive services and applications has improved the utility and the user experience of the Web, it has also made the development of Web applications much more complex. The main objective of this Thesis was to study how Web application development could be simplified by means of declarative programming. An extension that seamlessly integrates common server-side functionalities to the XForms markup language is proposed and its feasibility and capabilities are validated with a proof-of-concept implementation, called the XFormsDB framework, and two sample Web applications. The results show that useful, highly interactive multi-user Web applications can be authored quickly and easily in a single document and under a single programming model using the XFormsDB framework

The Family of MapReduce and Large Scale Data Processing Systems

In the last two decades, the continuous increase of computational power has produced an overwhelming flow of data which has called for a paradigm shift in the computing architecture and large scale data processing mechanisms. MapReduce is a simple and powerful programming model that enables easy development of scalable parallel applications to process vast amounts of data on large clusters of commodity machines. It isolates the application from the details of running a distributed program such as issues on data distribution, scheduling and fault tolerance. However, the original implementation of the MapReduce framework had some limitations that have been tackled by many research efforts in several followup works after its introduction. This article provides a comprehensive survey for a family of approaches and mechanisms of large scale data processing mechanisms that have been implemented based on the original idea of the MapReduce framework and are currently gaining a lot of momentum in both research and industrial communities. We also cover a set of introduced systems that have been implemented to provide declarative programming interfaces on top of the MapReduce framework. In addition, we review several large scale data processing systems that resemble some of the ideas of the MapReduce framework for different purposes and application scenarios. Finally, we discuss some of the future research directions for implementing the next generation of MapReduce-like solutions.Comment: arXiv admin note: text overlap with arXiv:1105.4252 by other author

Synthesis of Execution Plans for the QVT Core Language

Model transformation languages (MTLs) are important for Model Driven Engineering as they allow the automation of the engineering design process of hardware and software products, in particular at the preliminary and detailed design phases. However, the theories from compiler optimization have not been reused substantively in the development of MTLs. This makes the challenges associated with the implementation of declarative MTLs harder to overcome, in particular with respect to the synthesis of the execution plan (a representation of the control component of the transformation algorithm). The QVT Core MTL is a declarative language, part of a set of standards proposed by the Object Management Group® in order to support the adoption of Model Driven Engineering (MDE). This research presents how instruction scheduling theories can be used for the synthesis of execution plans, in particular for the QVT Core language. The main contributions are a novel approach for performing data dependence analysis on the QVT Core language and its use for the synthesis of execution plans, and the application of metaheuristics to solve the scheduling problem inherent to the synthesis of execution plans. The research demonstrated the feasibility of applying compiler optimization techniques in the design of MTLs and provides a methodology that can be used to construct effi cient execution plans that result in correct transformations. The performance gains and correctness will help the widespread use of the QVT Core language and encourage the adoption of compiler optimization techniques in the implementation of other MTLs

Bridging the Semantic Web and NoSQL Worlds: Generic SPARQL Query Translation and Application to MongoDB

International audienceRDF-based data integration is often hampered by the lack of methods to translate data locked in heterogeneous silos into RDF representations. In this paper, we tackle the challenge of bridging the gap between the Semantic Web and NoSQL worlds, by fostering the development of SPARQL interfaces to heterogeneous databases. To avoid defining yet another SPARQL translation method for each and every database, we propose a two-phase method. Firstly, a SPARQL query is translated into a pivot abstract query. This phase achieves as much of the translation process as possible regardless of the database. We show how optimizations at this abstract level can save subsequent work at the level of a target database query language. Secondly, the abstract query is translated into the query language of a target database, taking into account the specific database capabilities and constraints. We demonstrate the effectiveness of our method with the MongoDB NoSQL document store, such that arbitrary MongoDB documents can be aligned on existing domain ontologies and accessed with SPARQL. Finally, we draw on a real-world use case to report experimental results with respect to the effectiveness and performance of our approach