GIBRALTAR
The Global Info
Brokerage And Library Trading
Architecture
Introduction
Both technical and economical advances of
electronic communication system (such as the "Internet") have led - among
other things - to a world-wide infrastructure of cooperating service providers
and service consumers. This is in the meantime mostly addressed as a world-wide
open "Electronic Marketplace" which increasingly adds to both the proliferation
and the efficiency of global economic "Electronic Commerce".
Future digital libraries are as well part
of and profit from these developments: In such a view, both organisationally
as well as technically, advanced digital library systems are today composed
of a high number of distinct service providers and service consumers in
a modular way and, in general, in rather widely distributed environments.
For instance, such a service provider can be any (digital) information
service in the common sense; e.g. all sorts of databases accessible via
networks fall into this category.
The BMBF project GLOBAL INFO acknowledges
these developments and aims - among other things - at realising a (both
technical as well as organisational) open infrastructure for supporting
electronic exchange of (in this case: digital) information between providers
and consumers of such data based on existing global electronic communication
systems.
Additionally - and of special importance
for the GLOBAL INFO project environment - additional "value added" services
such as special "front ends" to existing (or legacy) databases, "viewers"
for different types of information, or specific "search engines" or notification
services (for instance such as an "alerting service" as proposed in a different
GLOBAL INFO sub-project) have to be provided in order to form rather important
additional modular service building blocks of distributed digital libraries
that shall exist in the future.
Due to the highly dynamic nature of such
global distributed environments, a rather crucial part in all large scale
distributed information retrieval environments is always the dynamic (!)
integration of new service providers at runtime and corresponding flexible
and convenient mechanisms for service users to specify their needs and
locate possible services that may fulfil them. As well as explicitly controlled
and triggered by the user himself, the location of service providers has
to take place "under the hood" to take account for the fact that any environment
made up from autonomous entities will have to face unpredictable disappearance
of service instances. It is this area, where "brokerage facilities" as
proposed in this sub-project form an important additional and integral
building block of any realistically flexible, robust, and user-friendly
distributed digital library system environment.
Goals
On the background of the above mentioned distributed
global and open information service environment, it is the central goal
of this GLOBAL INFO sub-project to design and realise a scalable, effective
and flexible facility to help to locate and use specific service instances
within the GLOBAL INFO architecture as efficiently and user-friendly as
(technically and economically) possible. Only given such a service, both
(information) service providers as well as (information) service consumers
are able to provide their respective services resp. address their respective
requests so autonomously as well as flexibly as required by open global
service markets.
For instance, using such a brokerage facility,
information service providers will then be able to define the characteristics
of the service they are willing to offer and advertise the service location
in, e.g., a globally accessible store. Each of such service offers will
then consist of service offer attributes to describe the service offer
(e.g. access costs of the service, type of information provided etc.),
a type description of the service offer and information on how where to
find the service provider. Appropriate definition schemes will have to
be developed to best support the context of digital library services. An
adjacent "type management engine" will help to define service classification
types. This type management engine will have to take account for the special
requirements within the digital library thus be designed and developed
within this sub-project.
To ensure maximum scalability and robustness
of such a component, a brokerage facility "federation mechanism" will be
designed and integrated into the brokerage facility. By means of this mechanism,
multiple instances of a brokerage facility can be interconnected to provide
a value added service to their user community. The broker federation mechanism
will be designed in a manner to allow for a seamless combination, where
all instances share and replicate the same offer space. Additionally, instances
of the brokerage facility will be able to make up a federation where each
instance will serve its own partition of the whole service offer space.
One of the primary goals of the BMBF GLOBAL INFO
project is to provide high numbers of user rather easy and effective access
to as many information services available as possible in a world-wide network
environment as the Internet. Especially for the Internet, locating suitable
service instances at runtime obviously imposes difficult technical requirements
on any support environment. Digital library sources have to be able to
define their service and advertise it accordingly. Scientists have to be
able to specify their needs and define queries to be able to find appropriate
digital library service instances as well as helper services such as special
visualisation services, billing services etc. Finally, the GLOBAL INFO
project has to provide a robust and reliable runtime environment where
disappearing services can be seamlessly substituted with different instances
at runtime. The brokerage facility as developed by the University of Hamburg
will exactly fill this gap. It will not only help integrating available
information sources as provided by participating publishing houses or third
party information providers, but also help to integrate services
developed within the GLOBAL INFO project to form a seamless and reliable
support environment within the digital library context.
Contact