Development of a product configuration system with an ontology-based approach

Abstract

Product configuration is a crucial means to implement the mass customization paradigm by assembling a set of customizable components to satisfy both customers’ needs and technical constraints. With the aim of enabling efficient and effective development of product configuration systems by reusing configuration knowledge, an ontology-based approach to modeling product configuration knowledge is presented in this paper. The ontology-based product configuration models are hierarchically organized. At the lower level, a configuration meta-model is defined. Based on this meta-model, domain-specific configuration knowledge can be derived by reusing or inheriting the classes or relations in the meta-model. Configuration models are formalized using OWL (Ontology Web Language), an ontology representation language developed by W3C. As a result, configuration models have well-defined semantics due to the logic semantics of OWL, making it possible to automatically detect inconsistencies of configuration knowledge bases. Furthermore, configuration constraints are represented in SWRL, a rule language based on OWL. Finally, actual configuration processes are carried out using JESS, a rule engine for the Java platform, by mapping OWL-based configuration facts and SWRL-based configuration constraints into JESS facts and JESS rules, respectively. The proposed methodology is illustrated with an example for configuring the ranger drilling machine.

Introduction

With the emerging paradigm of mass customization, products are designed into customizable modules or parts to meet individual needs of customers [1], [2]. With an increasing number of modules and parts in a customizable product, assembling these modules or parts into a legal constellation in a manual way becomes impracticable [3]. To reduce lead-time and shorten product cycle, product configuration technologies are developed to automate the processes of configuring a product [1], [2]. A product configuration system is defined as one that is capable of automatically or interactively configuring a product to satisfy both customers’ needs and technical constraints using product configuration technologies. The application of product configuration systems facilitates the sales-delivery process of products and avoids possible errors transferred between sale departments and engineering departments in manufacturing companies [4], [46].

The study of effective product configuration technologies has received much attention from the academic community and industry over years [1], [2], [3]. Previous research effort focused mainly on the actual configuration process for solving product configuration problems, such as the rule-based approach [5] and the CSP (Constraint Satisfaction Problem) approach [6], [7]. Recently, attention has been directed towards the study of conceptual modeling of customizable products, namely, product configuration models [8], [23], [44]. This is due to well-defined conceptual models being able to describe highly complex structures and constraints of customizable products. As a result, product configuration systems are able to deal with the problems of configuring complex products under mass customization. Furthermore, the reusability of configuration models can effectively reduce the time of developing product configuration systems. Ontology, which is defined as the conceptualization of terms and relations in a domain, offers a means to structurally represent and reuse domain knowledge [9]. In this paper, we address the modeling of product configuration knowledge with an ontology-based approach in which structural knowledge is formalized in OWL (Ontology Web Language) [10], [11], an ontology representation language developed by World Wide Web Consortium (W3C), and constraint knowledge in SWRL, (Semantic Web Rule Language) [12], a rule language based on OWL. Through the transformation of configuration knowledge into JESS facts and JESS rules, actual configuration processes are carried out with the support of JESS [13], a rule engine for the Java platform.

The remainder of this paper is organized as follows. The technical background is sketched in Section 2. Section 3 gives an overview of related work. In Section 4, we present a four-layer approach to modeling product configuration knowledge. Product configuration knowledge is then encoded using the ontology language, namely OWL and the rule language, i.e. SWRL, which is dealt with in Section 5. In Section 6, developing a product configurator based on the JESS rule engine is addressed. Finally, conclusions are drawn in Section 7.