13,660 research outputs found
Transparent Persistence with Java Data Objects
Flexible and performant Persistency Service is a necessary component of any
HEP Software Framework. The building of a modular, non-intrusive and performant
persistency component have been shown to be very difficult task. In the past,
it was very often necessary to sacrifice modularity to achieve acceptable
performance. This resulted in the strong dependency of the overall Frameworks
on their Persistency subsystems.
Recent development in software technology has made possible to build a
Persistency Service which can be transparently used from other Frameworks. Such
Service doesn't force a strong architectural constraints on the overall
Framework Architecture, while satisfying high performance requirements. Java
Data Object standard (JDO) has been already implemented for almost all major
databases. It provides truly transparent persistency for any Java object (both
internal and external). Objects in other languages can be handled via
transparent proxies. Being only a thin layer on top of a used database, JDO
doesn't introduce any significant performance degradation. Also Aspect-Oriented
Programming (AOP) makes possible to treat persistency as an orthogonal Aspect
of the Application Framework, without polluting it with persistence-specific
concepts.
All these techniques have been developed primarily (or only) for the Java
environment. It is, however, possible to interface them transparently to
Frameworks built in other languages, like for example C++.
Fully functional prototypes of flexible and non-intrusive persistency modules
have been build for several other packages, as for example FreeHEP AIDA and LCG
Pool AttributeSet (package Indicium).Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003. PSN TUKT00
A formal definition of the Users View (UV) of the Graphical Object Query Language (GOQL)
In this paper we provide a brief formal definition of the Users View (UV) of the Graphical Object Query Language(GOQL). The UV provides a graphical representation for object-oriented database schemas and hides from end-users most of the perplexing details of the object-oriented database model, such as methods, hierarchies and relationships. In particular, the UV does not distinguish between methods, attributes and relationships, encapsulates the is-a hierarchy and utilises a number of desktop metaphors to present a graphical schema that is easy to be understood by end-users. Thus, the UV provides the environment, through which end-users, can pose ad-hoc queries through GOQL. We first give a brief formal definition of an object-oriented database schema in the GOQL model. This is given, by providing a formal definition of the basic element of such a schema, namely the class. The UV is then briefly formally defined as a mapping from a GOQL object-oriented database schema. Using this mapping, any object-oriented database schema can be translated into a graphical representation in the UV. The running example of the paper is used to demonstrate the mapping from the textual schema to the graphical schema of the UV. The formal definition of the UV will allow us, in the future, to formally define the graphical constructs of
GOQL
An introduction to Graph Data Management
A graph database is a database where the data structures for the schema
and/or instances are modeled as a (labeled)(directed) graph or generalizations
of it, and where querying is expressed by graph-oriented operations and type
constructors. In this article we present the basic notions of graph databases,
give an historical overview of its main development, and study the main current
systems that implement them
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MultiView : a methodology for supporting multiple view schemata in object-oriented databases
It has been widely recognized that object-oriented database (OODB) technology needs to be extended to provide a mechanism similar to views in relational database systems. We define an object-oriented view to be an arbitrarily complex virtual schema graph with possibly restructured generalization and decomposition hierarchies - rather than just one virtual class as has been proposed in the literature. In this paper, we propose a methodology, called MultiView, for supporting multiple such view schemata. MultiView breaks the schema design task into the following independent and well-defined subtasks: (1) the customization of type descriptions and object sets of existing classes by deriving virtual classes, (2) the integration of all derived classes into one consistent global schema graph, and (3) the definition of arbitrarily complex view schemata on this augmented global schema. For the first task of MultiView, we define a set of object algebra operators that can be used by the view definer for class customization. For the second task of MultiView, we propose an algorithm that automatically integrates these newly derived virtual classes into the global schema. We solve the third task of MultiView by first letting the view definer explicitly select the desired view classes from the global schema using a view definition language and then by automatically generating a view class hierarchy for these selected classes. In addition, we present algorithms that verify the closure property of a view and, if found to be incomplete, transform it into a closed, yet minimal, view. In this paper, we introduce the fundamental concept of view independence and show MultiView to be view independent. We also outline implementation techniques for realizing MultiView with existing OODB technology
Past, present and future of information and knowledge sharing in the construction industry: Towards semantic service-based e-construction
The paper reviews product data technology initiatives in the construction sector and provides a synthesis of related ICT industry needs. A comparison between (a) the data centric characteristics of Product Data Technology (PDT) and (b) ontology with a focus on semantics, is given, highlighting the pros and cons of each approach. The paper advocates the migration from data-centric application integration to ontology-based business process support, and proposes inter-enterprise collaboration architectures and frameworks based on semantic services, underpinned by ontology-based knowledge structures. The paper discusses the main reasons behind the low industry take up of product data technology, and proposes a preliminary roadmap for the wide industry diffusion of the proposed approach. In this respect, the paper stresses the value of adopting alliance-based modes of operation
London SynEx Demonstrator Site: Impact Assessment Report
The key ingredients of the SynEx-UCL software components are:
1. A comprehensive and federated electronic healthcare record that can be used to
reference or to store all of the necessary healthcare information acquired from a
diverse range of clinical databases and patient-held devices.
2. A directory service component to provide a core persons demographic database to
search for and authenticate staff users of the system and to anchor patient
identification and connection to their federated healthcare record.
3. A clinical record schema management tool (Object Dictionary Client) that enables
clinicians or engineers to define and export the data sets mapping to individual
feeder systems.
4. An expansible set of clinical management algorithms that provide prompts to the
patient or clinician to assist in the management of patient care.
CHIME has built up over a decade of experience within Europe on the requirements
and information models that are needed to underpin comprehensive multiprofessional
electronic healthcare records. The resulting architecture models have
influenced new European standards in this area, and CHIME has designed and built
prototype EHCR components based on these models. The demonstrator systems
described here utilise a directory service and object-oriented engineering approach,
and support the secure, mobile and distributed access to federated healthcare
records via web-based services.
The design and implementation of these software components has been founded on
a thorough analysis of the clinical, technical and ethico-legal requirements for
comprehensive EHCR systems, published through previous project deliverables and
in future planned papers.
The clinical demonstrator site described in this report has provided the solid basis
from which to establish "proof of concept" verification of the design approach, and a
valuable opportunity to install, test and evaluate the results of the component
engineering undertaken during the EC funded project. Inevitably, a number of
practical implementation and deployment obstacles have been overcome through
this journey, each of those having contributed to the time taken to deliver the
components but also to the richness of the end products.
UCL is fortunate that the Whittington Hospital, and the department of cardiovascular
medicine in particular, is committed to a long-term vision built around this work. That
vision, outlined within this report, is shared by the Camden and Islington Health
Authority and by many other purchaser and provider organisations in the area, and
by a number of industrial parties. They are collectively determined to support the
Demonstrator Site as an ongoing project well beyond the life of the EC SynEx
Project.
This report, although a final report as far as the EC project is concerned, is really a
description of the first phase in establishing a centre of healthcare excellence. New
EC Fifth Framework project funding has already been approved to enable new and
innovative technology solutions to be added to the work already established in north
London
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