48,138 research outputs found
Global Grids and Software Toolkits: A Study of Four Grid Middleware Technologies
Grid is an infrastructure that involves the integrated and collaborative use
of computers, networks, databases and scientific instruments owned and managed
by multiple organizations. Grid applications often involve large amounts of
data and/or computing resources that require secure resource sharing across
organizational boundaries. This makes Grid application management and
deployment a complex undertaking. Grid middlewares provide users with seamless
computing ability and uniform access to resources in the heterogeneous Grid
environment. Several software toolkits and systems have been developed, most of
which are results of academic research projects, all over the world. This
chapter will focus on four of these middlewares--UNICORE, Globus, Legion and
Gridbus. It also presents our implementation of a resource broker for UNICORE
as this functionality was not supported in it. A comparison of these systems on
the basis of the architecture, implementation model and several other features
is included.Comment: 19 pages, 10 figure
Storage Solutions for Big Data Systems: A Qualitative Study and Comparison
Big data systems development is full of challenges in view of the variety of
application areas and domains that this technology promises to serve.
Typically, fundamental design decisions involved in big data systems design
include choosing appropriate storage and computing infrastructures. In this age
of heterogeneous systems that integrate different technologies for optimized
solution to a specific real world problem, big data system are not an exception
to any such rule. As far as the storage aspect of any big data system is
concerned, the primary facet in this regard is a storage infrastructure and
NoSQL seems to be the right technology that fulfills its requirements. However,
every big data application has variable data characteristics and thus, the
corresponding data fits into a different data model. This paper presents
feature and use case analysis and comparison of the four main data models
namely document oriented, key value, graph and wide column. Moreover, a feature
analysis of 80 NoSQL solutions has been provided, elaborating on the criteria
and points that a developer must consider while making a possible choice.
Typically, big data storage needs to communicate with the execution engine and
other processing and visualization technologies to create a comprehensive
solution. This brings forth second facet of big data storage, big data file
formats, into picture. The second half of the research paper compares the
advantages, shortcomings and possible use cases of available big data file
formats for Hadoop, which is the foundation for most big data computing
technologies. Decentralized storage and blockchain are seen as the next
generation of big data storage and its challenges and future prospects have
also been discussed
A Taxonomy of Data Grids for Distributed Data Sharing, Management and Processing
Data Grids have been adopted as the platform for scientific communities that
need to share, access, transport, process and manage large data collections
distributed worldwide. They combine high-end computing technologies with
high-performance networking and wide-area storage management techniques. In
this paper, we discuss the key concepts behind Data Grids and compare them with
other data sharing and distribution paradigms such as content delivery
networks, peer-to-peer networks and distributed databases. We then provide
comprehensive taxonomies that cover various aspects of architecture, data
transportation, data replication and resource allocation and scheduling.
Finally, we map the proposed taxonomy to various Data Grid systems not only to
validate the taxonomy but also to identify areas for future exploration.
Through this taxonomy, we aim to categorise existing systems to better
understand their goals and their methodology. This would help evaluate their
applicability for solving similar problems. This taxonomy also provides a "gap
analysis" of this area through which researchers can potentially identify new
issues for investigation. Finally, we hope that the proposed taxonomy and
mapping also helps to provide an easy way for new practitioners to understand
this complex area of research.Comment: 46 pages, 16 figures, Technical Repor
Handling Confidential Data on the Untrusted Cloud: An Agent-based Approach
Cloud computing allows shared computer and storage facilities to be used by a
multitude of clients. While cloud management is centralized, the information
resides in the cloud and information sharing can be implemented via
off-the-shelf techniques for multiuser databases. Users, however, are very
diffident for not having full control over their sensitive data. Untrusted
database-as-a-server techniques are neither readily extendable to the cloud
environment nor easily understandable by non-technical users. To solve this
problem, we present an approach where agents share reserved data in a secure
manner by the use of simple grant-and-revoke permissions on shared data.Comment: 7 pages, 9 figures, Cloud Computing 201
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
Grid Databases for Shared Image Analysis in the MammoGrid Project
The MammoGrid project aims to prove that Grid infrastructures can be used for
collaborative clinical analysis of database-resident but geographically
distributed medical images. This requires: a) the provision of a
clinician-facing front-end workstation and b) the ability to service real-world
clinician queries across a distributed and federated database. The MammoGrid
project will prove the viability of the Grid by harnessing its power to enable
radiologists from geographically dispersed hospitals to share standardized
mammograms, to compare diagnoses (with and without computer aided detection of
tumours) and to perform sophisticated epidemiological studies across national
boundaries. This paper outlines the approach taken in MammoGrid to seamlessly
connect radiologist workstations across a Grid using an "information
infrastructure" and a DICOM-compliant object model residing in multiple
distributed data stores in Italy and the UKComment: 10 pages, 5 figure
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