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A practical mandatory access control model for XML databases
A practical mandatory access control (MAC) model for XML databases is presented in this paper. The
label type and label access policy can be defined according to the requirements of different applications. In order to
preserve the integrity of data in XML databases, a constraint between a read-access rule and a write-access rule in
label access policy is introduced. Rules for label assignment and propagation are presented to alleviate the workload
of label assignments. Furthermore, a solution for resolving conflicts in label assignments is proposed. Rules for
update-related operations, rules for exceptional privileges of ordinary users and the administrator are also proposed
to preserve the security of operations in XML databases. The MAC model, we proposed in this study, has been
implemented in an XML database. Test results demonstrated that our approach provides rational and scalable
performance
Recommended from our members
Integration with Ontologies
One of todayâs hottest IT topics is integration, as bringing together information from different sources and structures is not completely solved. The approach outlined here wants to illustrate how ontologies [Gr93] could help to support the integration process
Data integration through service-based mediation for web-enabled information systems
The Web and its underlying platform technologies have often been used to integrate existing software and information systems. Traditional techniques for data representation and transformations between documents are not sufficient to support a flexible and maintainable data integration solution that meets the requirements of modern complex Web-enabled software and information systems. The difficulty
arises from the high degree of complexity of data structures, for example in business and technology applications, and from the constant change of data and its
representation. In the Web context, where the Web platform is used to integrate different organisations or software systems, additionally the problem of heterogeneity
arises. We introduce a specific data integration solution for Web applications such as Web-enabled information systems. Our contribution is an integration technology
framework for Web-enabled information systems comprising, firstly, a data integration technique based on the declarative specification of transformation rules and the construction of connectors that handle the integration and, secondly, a mediator architecture based on information services and the constructed connectors to handle the integration process
XML Matchers: approaches and challenges
Schema Matching, i.e. the process of discovering semantic correspondences
between concepts adopted in different data source schemas, has been a key topic
in Database and Artificial Intelligence research areas for many years. In the
past, it was largely investigated especially for classical database models
(e.g., E/R schemas, relational databases, etc.). However, in the latest years,
the widespread adoption of XML in the most disparate application fields pushed
a growing number of researchers to design XML-specific Schema Matching
approaches, called XML Matchers, aiming at finding semantic matchings between
concepts defined in DTDs and XSDs. XML Matchers do not just take well-known
techniques originally designed for other data models and apply them on
DTDs/XSDs, but they exploit specific XML features (e.g., the hierarchical
structure of a DTD/XSD) to improve the performance of the Schema Matching
process. The design of XML Matchers is currently a well-established research
area. The main goal of this paper is to provide a detailed description and
classification of XML Matchers. We first describe to what extent the
specificities of DTDs/XSDs impact on the Schema Matching task. Then we
introduce a template, called XML Matcher Template, that describes the main
components of an XML Matcher, their role and behavior. We illustrate how each
of these components has been implemented in some popular XML Matchers. We
consider our XML Matcher Template as the baseline for objectively comparing
approaches that, at first glance, might appear as unrelated. The introduction
of this template can be useful in the design of future XML Matchers. Finally,
we analyze commercial tools implementing XML Matchers and introduce two
challenging issues strictly related to this topic, namely XML source clustering
and uncertainty management in XML Matchers.Comment: 34 pages, 8 tables, 7 figure
Design of the shared Environmental Information System (SEIS) and development of a web-based GIS interface
Chapter 5The Shared Environmental Information System (SEIS) is a collaborative initiative of
the European Commission (EC) and the European Environment Agency (EEA) aimed to
establish an integrated and shared EU-wide environmental information system together
with the Member States.
SEIS presents the European vision on environmental information interoperability. It is
a set of high-level principles & workflow-processes that organize the collection, exchange,
and use of environmental data & information aimed to:
⢠Modernise the way in which information required by environmental legislation is
made available to member states or EC instruments;
⢠Streamline reporting processes and repeal overlaps or obsolete reporting obligations;
⢠Stimulate similar developments at international conventions;
⢠Standardise according to INSPIRE when possible; and
⢠Introduce the SDI (spatial database infrastructure) principle EU-wide.
SEIS is a system and workflow of operations that offers technical capabilities geared to
meet concept expectations. In that respect, SEIS shows the way and sets up the workflow
effectively in a standardise way (e.g, INSPIRE) to:
⢠Collect Data from Spatial Databases, in situ sensors, statistical databases, earth
observation readings (e.g., EOS, GMES), marine observation using standard data
transfer protocols (ODBC, SOS, ft p, etc).
⢠Harmonise collected data (including data check/data integrity) according to best
practices proven to perform well, according to the INSPIRE Directive 2007/2/EC
(1) Annexes I: II: III: plus INSPIRE Implementation Rules for data not specified in
above mentioned Annexes.
⢠Harmonise collected data according to WISE (Water Information System from
Europe) or Ozone-web.
⢠Process, aggregate harmonise data so to extract information in a format understandable
by wider audiences (e.g., Eurostat, enviro-indicators).
⢠Document information to fulfi l national reporting obligations towards EU bodies
(e.g., the JRC, EEA, DGENV, Eurostat)
⢠Store and publish information for authorised end-users (e.g., citizens, institutions).
This paper presents the development and integration of the SEIS-Malta Geoportal.
The first section outlines EU Regulations on INSPIRE and Aarhus Directives. The second
covers the architecture and the implementation of SEIS-Malta Geoportal. The third
discusses the results and successful implementation of the Geoportal.peer-reviewe
HUDDL for description and archive of hydrographic binary data
Many of the attempts to introduce a universal hydrographic binary data format have failed or have been only partially successful. In essence, this is because such formats either have to simplify the data to such an extent that they only support the lowest common subset of all the formats covered, or they attempt to be a superset of all formats and quickly become cumbersome. Neither choice works well in practice. This paper presents a different approach: a standardized description of (past, present, and future) data formats using the Hydrographic Universal Data Description Language (HUDDL), a descriptive language implemented using the Extensible Markup Language (XML). That is, XML is used to provide a structural and physical description of a data format, rather than the content of a particular file. Done correctly, this opens the possibility of automatically generating both multi-language data parsers and documentation for format specification based on their HUDDL descriptions, as well as providing easy version control of them. This solution also provides a powerful approach for archiving a structural description of data along with the data, so that binary data will be easy to access in the future. Intending to provide a relatively low-effort solution to index the wide range of existing formats, we suggest the creation of a catalogue of format descriptions, each of them capturing the logical and physical specifications for a given data format (with its subsequent upgrades). A C/C++ parser code generator is used as an example prototype of one of the possible advantages of the adoption of such a hydrographic data format catalogue
HepData and JetWeb: HEP data archiving and model validation
The CEDAR collaboration is extending and combining the JetWeb and HepData
systems to provide a single service for tuning and validating models of
high-energy physics processes. The centrepiece of this activity is the fitting
by JetWeb of observables computed from Monte Carlo event generator events
against their experimentally determined distributions, as stored in HepData.
Caching the results of the JetWeb simulation and comparison stages provides a
single cumulative database of event generator tunings, fitted against a wide
range of experimental quantities. An important feature of this integration is a
family of XML data formats, called HepML.Comment: 4 pages, 0 figures. To be published in proceedings of CHEP0
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