LCA-oriented semantic representation for the product life cycle

In order to complete a life cycle assessment (LCA) study of the product, each activity interacting with the environment during the product life cycle should be given an explicit description, namely an LCA-oriented representation for the product life cycle should be constructed. A complex functional product usually consists of many parts made of different materials and its LCA-oriented life cycle modeling involves many complex semantic relationships. In this paper, a new LCA-oriented and ontology-based semantic representation model and methodology for the product life cycle are proposed. First, the concepts of processes and flows, and the semantic relationships among processes, and between processes and flows are analyzed in detail. The ontology classes of processes and flows are defined using the Web Ontology Language (OWL). Then, an LCA-oriented semantic concept model for the product life cycle is presented. Based on the proposed semantic representation model, all processes, flows, and the relationships among them can be represented as a Resource Description Framework (RDF) graph in which each node is an instance tagged by an ontology class. A formalization of lifecycle processes on flows is provided, which can be encoded with Semantic Web Rule Language (SWRL) and formed into a knowledge rule base. In addition, a semantic query method for the life cycle inventory of a product is proposed. Finally, an implementation framework and an example of the semantic representation for a ball bearing's life cycle are provided.