Environmental Engineering Reference
In-Depth Information
OpenMI and Model Linking
Although the SeamFrame application server operates in Java environment, the
model components can be implemented using other languages as long as they can be
integrated. This requirement has been translated into the fact that model components
should be OpenMI
9
compliant, by implementing the OpenMI interfaces and allow
linking to other components (for data exchange). The model component can take
care of this by itself or a wrapper or bridge can be programmed.
The Open Modelling Interface and Environment (
www.openmi.org
) has been
developed from the need to answer questions related to integrated hydrologi-
cal management of catchments within the EU fifth framework program project
HarmonIT (
www.harmonit.org
)
. OpenMI provides a standardized interface for data
exchange between software components that run sequentially, based on a
pipes and
filters architecture
(Gregersen et al.
2007)
. Since the release of the OpenMI in early
2006 the environmental domain adopted the OpenMI within several European
projects. This introduced new requirements, which were implemented, resulting in
a new OpenMI version (Verweij et al.
2007)
. Examples of these projects are:
-
SEAMLESS - assess agricultural and agro-environmental policies;
-
SENSOR - assess sustainability impacts of land use related policies;
-
NitroEurope - assess the effects of reactive nitrogen in the environment;
-
EFORWOOD - assess sustainability impacts of European forest wood chains.
These projects have a strong integrated character: environmental, social and
economic dimensions are taken into account to perform an ex-ante integrated
assessment. An IA can be defined as an interdisciplinary process of combining,
interpreting and communicating knowledge from diverse scientific disciplines in
such a way that the whole cause-effect chain of a problem can be evaluated from a
synoptic perspective with two characteristics:
•
It should have added value compared to single disciplinary assessment.
•
It should provide useful information to decision makers (Rotmans and Dowlatabadi
1998)
.
OpenMI provides a standardized interface to define, describe and transfer (numerical)
data between software components. The data definition concerns what the data is
about (
quantity
) and where (
element set
) and when (
time
) it applies. Each component
(
LinkableComponent
) has a meta data description of its exchangeable data in terms
of a
quantity
and an
element set
. Each unique exchangeable
quantity
is registered
and published in a so-called
ExchangeItem
. Connections between
ExchangeItems
of
LinkableComponents
are defined by a
Link
and exist as a separate entity (Fig.
9.7
).
For more information see
http://www.openmi.org
.
OpenMI is a pull-based system (a pipes and filters architecture). Figure
9.8
shows how the chain of
LinkableComponents
is triggered (step one) by a successive
