OpenDT: A Reference Framework for Service Publication and Discovery using Remote Programmable Digital Twins

Traditional service registries or catalogs publish and describe individual services of different entities. In this paper, we propose a new approach of service publication and discovery based on the philosophy of "product catalogs". In this new approach, entities are equivalent to products in typical products catalogs. We conceptualize an entity registry where each entry constitutes to its collection of remote services. For logical abstraction of entities, we utilize the concept of Digital Twin (DT). To support our objective, we present a reference DT architecture that virtualizes entities, exposes all its functionalities as services, and offers a remote programmable instance to invoke the services directly from application code. To publish and discover DTs, we propose a novel framework, OpenDT. This framework enables entity owners to publish DTs and allow users to discover them for creating mashups and applications using DT services. It also allows developers to create composite DTs that consists of other DTs for large and complex entities. To evaluate OpenDT, we implement a cyber-manufacturing testbed comprising of multiple machining tools and their DTs. Case validations from testbed show excellent efficiency of DT-driven entity publication and discovery.