A Web-Based Software System for Model Integration in Impact Assessments of Agricultural and Environmental Policies - Environmental and Agricultural Modelling - page 204

The development of a common ontology by a group of researchers is a complex,
challenging and time-consuming task (Farquhar et al. 1995 ; Gruber 1993) , and it
still remains a scientific challenge. To achieve ontological commitment, i.e. the
agreement by multiple parties to adhere to a common ontology, when these parties
do not have the same experiences and theories (Holsapple and Joshi 2002) , a
collaborative approach is needed (Pennington et al. 2007) . Other approaches for
ontology development are the inspirational approach, the inductive approach,
the deductive approach and the synthetic approach (Holsapple and Joshi 2002) .
A collaborative approach has the advantages that researchers from different
disciplines are diverse in their contributions, which avoids blind spots and which
has more chances of getting a wide acceptance (Holsapple and Joshi 2002) .
The Role of Ontologies in SEAMLESS
The Structure of SEAMLESS-IF Framework
The SEAMLESS consortium develops a computerized and integrated framework
(SEAMLESS-IF) to assess the impacts on environmental and economic sustainability
of a wide range of policies and technological improvements across a number of
scales (Van Ittersum et al. 2008) . In the SEAMLESS-IF approach different type of
models and indicators are linked into a type of scientific workflows (van der Aalst
and van der Hee 2002) named model chains , where each model uses the outputs of
another model as its inputs and ultimately indicators are calculated. With respect to
the models (Fig. 9.3 ), macro-level economic partial equilibrium models (GTAP and
CAPRI; Britz et al. 2007) are linked to micro-level farm optimization models
(FSSIM-MP and FSSIM-AM; see chapter 5 of this volume) and field crop growth
models (APES; cf. Van Ittersum and Donatelli 2003 - see Chapter 4 of this Volume),
using micro-macro up scaling methods (EXPAMOD; Bezlepkina et al. 2007) . The
macro-level economic partial equilibrium models simulate markets for agricultural
commodities and trade between the European Union and other world trading blocks
and the micro-level farm optimization problems allocate the farm area to different
agricultural activities based on farmer objectives and available farm resources.
Examples of agricultural activities are growing a wheat-sugar beet rotation with
intensive management or keeping dairy cattle for the production of milk. The agri-
cultural activities for cropping systems can be evaluated by the field crop growth
models on their yield and environmental effects (e.g. nitrate leaching, pesticide
leaching, soil erosion). Finally the micro-macro up-scaling methods extrapolate on
the basis of the micro-level behaviour of the optimization model FSSIM-MP price-
elasticities that are an input to the macro level partial equilibrium model CAPRI.
These models provide, through their outputs, the basis for the calculation of indicators
of interest to the user. Each of these models are derived from different disciplines,
operate on different time and spatial scales, are programmed in different programming
languages and have a different implementation of scenarios.