Instance-Independent View Serializability for Semistructured Databases

Semistructured databases require tailor-made concurrency control mechanisms since traditional solutions for the relational model have been shown to be inadequate. Such mechanisms need to take full advantage of the hierarchical structure of semistructured data, for instance allowing concurrent updates of subtrees of, or even individual elements in, XML documents. We present an approach for concurrency control which is document-independent in the sense that two schedules of semistructured transactions are considered equivalent if they are equivalent on all possible documents. We prove that it is decidable in polynomial time whether two given schedules in this framework are equivalent. This also solves the view serializability for semistructured schedules polynomially in the size of the schedule and exponentially in the number of transactions

Modeling temporal dimensions of semistructured data

In this paper we propose an approach to manage in a correct way valid time semantics for semistructured temporal clinical information. In particular, we use a graph-based data model to represent radiological clinical data, focusing on the patient model of the well known DICOM standard, and define the set of (graphical) constraints needed to guarantee that the history of the given application domain is consistent

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

Collaborative software agents support for the texpros document management system

This dissertation investigates the use of active rules that are embedded in markup documents. Active rules are used in a markup representation by integrating Collaborative Software Agents with TEXPROS (abbreviation for TEXt PROcessing System) [Liu and Ng 1996] to create a powerful distributed document management system. Such markup documents with embedded active rules are called Active Documents. For fast retrieval purposes, when we need to generate a customized Internet folder organization, we first define the Folder Organization Query Language (FO-QL) to solve data categorization problems. FO-QL defines the folder organization query process that automatically retrieves links of documents deposited into folders and then constructs a folder organization in either a centralized document repository or multiple distributed document repositories. Traditional documents are stored as static data that do not provide any dynamic capabilities for accessing or interacting with the document environment. The dynamic and distributed nature of both markup data and markup rules do not merely respond to requests for information, but intelligently anticipate, adapt, and actively seek ways to support the computing processes. This outcome feature conquers the static nature of the traditional documents. An Office Automation Definition Language (OADL) with active rules is defined for constructing the TEXPROS \u27s dual modeling approach and workflow events representation. Active Documents are such agent-supported OADL documents. With embedded rules and self-describing data features, Active Documents provide capability of collaborative interactions with software agents. Data transformation and data integration are both data processing problems but little research has focused on the markup documents to generate a versatile folder organization. Some of the research merely provides manual browsing in a document repository to find the right document. This browsing is time consuming and unrealistic, especially in multiple document repositories. With FO-QL, one can create a customized folder organization on demand

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

A graph-based meta-model for heterogeneous data management

The wave of interest in data-centric applications has spawned a high variety of data models, making it extremely difficult to evaluate, integrate or access them in a uniform way. Moreover, many recent models are too specific to allow immediate comparison with the others and do not easily support incremental model design. In this paper, we introduce GSMM, a meta-model based on the use of a generic graph that can be instantiated to a concrete data model by simply providing values for a restricted set of parameters and some high-level constraints, themselves represented as graphs. In GSMM, the concept of data schema is replaced by that of constraint, which allows the designer to impose structural restrictions on data in a very flexible way. GSMM includes GSL, a graph-based language for expressing queries and constraints that besides being applicable to data represented in GSMM, in principle, can be specialised and used for existing models where no language was defined. We show some sample applications of GSMM for deriving and comparing classical data models like the relational model, plain XML data, XML Schema, and time-varying semistructured data. We also show how GSMM can represent more recent modelling proposals: the triple stores, the BigTable model and Neo4j, a graph-based model for NoSQL data. A prototype showing the potential of the approach is also described

What are Decision Support Systems?

Decision Support Systems (DSS) are a new kind of information systems as yet not well understood by managers or even by researchers in management science. The purpose of this paper is to present, as simply as possible, the concept underlying DSS, to discuss its applications to management and to examine some of the concerns managers might have regarding DSS. It is important to understand DSS because they offer managers the opportunity to directly improve their managerial effectiveness

A Modal Logical Approach for Developing XML Databases

This paper investigates the possibility of realizing the core of an XML database system by a pure modal logical formalism providing query and constraint languages with well-defined syntax semantics and computational elements. The paper also introduces a domain-specific modal logic for XML documents which can be used to implement some of the basic services of an XML database