(408e) Ontology Engineering Approach to Support Process Model Integration

Ontology engineering
approach to support process model integration

Linsey Koo, Nikolaos
Trokanas, Franjo Cecelja

PRISE Group, Chemical and
Process System Engineering, Faculty of Engineering and Physical Sciences, University
of Surrey, Guildford, Surrey, U. K.

Process
modelling and simulation is a vital tool to plan, evaluate, assess, and develop
different alternatives for the design of products and processes. The complexity
of problems as well as heterogeneity of modelling methods make process
modelling and simulation challenging, time consuming and often tedious process
requiring a wide range of expertise. Inconsistencies in model development are
the main cause for redundant work.  Models remain implicit to the engineers who
have built them, which further limits the potential of reusability.

The only model
integration framework in use, the CAPE-OPEN, addresses the issue of
standardisation of interfaces to enable interoperability between simulator
software components from different sources. It is the framework built around a
middleware, the Common Object Request Broker Architecture (CORBA) that hosts
communication between unit operations defined for a specific function and the
process modelling environments. The standard specification is defined as a
property package which is needed for a thermodynamic or physical property
calculation. The interoperability of models, such as model selection, parameter
identification, and experimental work is enabled through the connection related
to the unit operations and physical properties. It is not necessary to match
all parameters in order to facilitate Input-Output (I-O) matching. However, the
shortcoming of the CAPE-OPEN is in the need for identifying key variables for
each unit operation.

A new
approach for model integration however builds upon the CAPE-OPEN framework
proposes   the use of ontology and replaces the CORBA object bus with more
flexible semantic repository (Koo and Cecelja, 2015).
Models are described by Semantic Web Services (SWS) using Ontology Web
Service Description (OWL-S) as an enabler of web services through service
discovery, selection, composition, and execution stages, as shown in Figure 1. The
discovery stage allows formation of an integrated model through matching requests
from a public repository(ies). The best match that satisfy the requestor's
functionality is selected in the model selection stage. The model composition
stage then formulates the chain of integrated models and execution of
integrated model takes place during the execution stage.

Figure 1. Semantically described
model

This paper
focuses on the matching parameters related to the domain of process system
engineering, with emphasis placed on the role of physical properties and unit
operation. We propose an extension of classification of variables defined by
CAPE-OPEN with adaptation to ontology. To this end, each model representing a
device (e.g. unit operations, flowsheets, subflowsheets etc.) is semantically
described in domain ontology including domain assumptions and descriptions of
the functionality of the model. The domain ontology guides the process of
registering models and instantiation of ontology through ontology parsing. The
domain ontology makes the model and data explicit and sharing terminology
improves consistency. The devices in a process are connected via streams that
transmit information through multiple inlets and outlets from one unit to the
other. The connection between devices are described in ontology by introducing
the concept of ?ports' and ?connections' (CO-LaN, 2014). The ?ports' generally
describe inlets and outlets of devices and three different types of streams are
distinguished: material, energy, and information, which are further described
by object properties. The ?connections' are the object that is responsible for
establishing a link between two ports, which contains information regarding
methods, types, quantities, and units of streams.

The
structural concept and classification of matching parameters defined by
CAPE-OPEN have been employed in ontology. It intends to guide through the
complexity of modelling methods and to facilitate I-O matching, while
demonstrating the flexibility of model integration. To highlight the main
feature of the ontology approach model integration, manageable scale models
related to bio-refining process are used to verify the performance of the
proposed approach.

References:

CO-LaN,
2014, Conceptual Design Document for CAPE-Open Project, www.co-lan.org [Accessed
on 20/04/2015]

Koo, L.,
Cecelja, F., 2015, Model Integration Using Ontology Input-Output Matching, 25^th
European Symposium on Computer Aided Process Engineering Proceeding Book,
Copenhagen, Denmark, pp. 2567