Towards the Integration of Lightweight Components in Cyber-Physical Systems

Abstract Cyber-Physical Systems (CPS) integrate computation and physical processes, often leveraging Internet of Things (IoT) devices. A key challenge is managing the complexity and resource constraints in these systems. The Web of Things (WoT) paradigm offers standardization through servients, but traditional implementations that embed communication servers for each protocol can increase resource demands, especially as the system scales. This paper proposes WoT-Core, an architectural blueprint for implementing lightweight WoT servients to mitigate these challenges. Our approach shifts implementation complexity from individual servients to external, centralized brokers. Servients act solely as clients connecting to intermediary brokers that manage protocol-specific communication. This model aims to reduce deployment complexity and servient processing load. We detail the architecture, the role of Thing Descriptions, the initialization process, and an inter-thing communication mechanism facilitated by a dedicated ’connector’ component. The feasibility and trade-offs of the architecture are evaluated through a smart home application scenario, including a quantitative analysis of resource consumption and response latency compared to a traditional approach as the number of devices increases. This work contributes a refined architectural pattern for building more scalable and maintainable WoT-based CPS, demonstrating a significant reduction in servient resource usage at the cost of increased communication latency, a trade-off beneficial for many large-scale, non-time-critical deployments.