Several of the projects have documented their architectures in some detail, and readers are advised
to look at these in drawing up their own.
De Montfort
http://mle.dmu.ac.uk/deliver/dmu_MLE_Architecture_v1_000.doc
describes the
architecture both in terms of the realtionships between systems and protocols and standards used
to achieve this and states "The architecture used to integrate the MLE with internal DMU systems
has been designed so that it is generic enough to be implemented into other, similar,
environments. This is supported by the use of widely recognised standards such as XML, IMS and
SQL. We have tested extending the scope of this client to searching our Institutional Finance
System (this is from the same vendor as the QLS system, but the principle is that it is an SQL
database that can be registered with MS Windows NT, as an ODBC/ADO database)." The
architecture of the MLE front end to QLS student record system can be found at
http://mle.dmu.ac.uk/deliver/DMU_MLE_QLS_Broker_Documentation_5_3b_v1_002.doc
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Presentation Layer
The presentation layer provides a variety of user views of the data and allows and user input to
work with the system. The system allows the user to select their preferences for which data is
displayed and how. The system will also detect what browser is being used and depending
upon that and the users preferences provide the most appropriate user experience.
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Abstract Information Toolkit
This layer represents the engine room of the system providing data translation facilities from
the system specific external view of the data to the internal abstract representation. Once the
data has been translated it is made available to the presentation layer for display and
manipulation.
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Systems Interface Layer
The systems interface is the lowest level of the system and it is this layer, which broadly
communicates with the external systems. The systems interfaced to this layer are on the
whole data sources that are consulted to populated the users view. There is the option in the
design for data updating as well as lookup. The ability to perform this task is dependent on the
toolkit definitions in the layer above.
St Andrews came up with a five tiered model "The (INSIDE) pilot system is composed of five tiers,
which consist of a client (tier 0), the middle tier - the JSP (tier 1), which interacts with the back end
resources - database (tier 3) and the other remote objects (tier4) via Enterprise JavaBeans (EJB)
component (tier 2). The EJB server and the EJB provide managed access to resources, support
transactions and access to underlying security mechanisms, thus addressing the resource sharing
and performance issues. see for instance
http://www.dcs.st-
and.ac.uk/inside/reports/wse2002_paper.pdf 
