Environmental Engineering Reference
In-Depth Information
An Architecture for Knowledge Integration in Integrated
Assessment Studies
The SEAMLESS-IF Architecture
A keystone of the SEAMLESS project is the software architecture enabling and
supporting the development of integrated assessment studies. The global architecture
of SEAMLESS-IF is typical for a layered (multi-tier) web based application.
The diagram in Fig.
9.4
illustrates this architecture.
The principle of dividing a software system into layers reaches back to the early
days of computer science (Dahl et al.
1968)
. Originally the idea was used for the
design of operating systems but it applies equally well to other types of software.
In the layered software architecture the system's functionality is usually separated
in a persistence layer for storage of domain object state, a domain layer for the
domain model and domain logic, a services layer that controls transactions and
contains the business logic, an application layer for use-case workflows, syntactic
validation and interaction with the services layer and finally a presentation layer for
the user interfaces. As a general rule each layer has only dependencies on those
below it, not above, limiting the effect of changes and increasing maintainability.
In a way each layer acts as a client to the tier below and as a server to the tier above.
All layers can be located on a single computer, or they can be divided amongst a
number of systems. The latter is the case for SEAMLESS-IF.
Fig. 9.4
The SEAMLESS-IF architecture on the right is composed by three layers (SeamFrame,
the core framework; SeamServer, the server side services; SeamGUI the client-based graphical
user interface) and by external modules such as OpenMI compliant models, a set of ontologies
managed by the Knowledge Manager and the SEAMLESS database
