(183o) Ontology Engineering Approach to Support Process of Model Integration

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.

In this paper a new approach for model integration is proposed which builds upon the CAPE-OPEN framework and proposes the use of ontology and replaces the object bus with more flexible semantic repository (Koo, Trokanas and Cecelja, 2017). 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 (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. 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. 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, which makes the model and data explicit and sharing terminology in domain ontology 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’. 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 objective 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.