HpC: A Calculus for Hybrid and Mobile Systems -- Full Version

2025-01-16

AI Summary

Modeling and verifying IoT systems is challenging due to the intertwined dynamics of mobile devices, time-varying network topologies, and continuously evolving physical environments. Method: This paper introduces HpC—the first hybrid process calculus that minimally and conservatively extends the π-calculus with explicit representations of time and physical dynamics. HpC uniformly captures discrete communication, dynamic connectivity, and continuous physical evolution, enabling formal modeling of mobility, universality, and hybridity. Contribution/Results: Building upon HpC, we integrate hybrid-system semantics, behavioral equivalences (e.g., bisimulation), and real-time protocol analysis techniques to achieve the first end-to-end formal modeling and reliability verification of a real-world mobile device handover protocol. Our approach rigorously guarantees behavioral correctness under continuous environmental changes, thereby establishing a foundational framework for formally reasoning about safety-critical IoT protocols.

Technology Category

• Application Domains: Internet of Things, Sensor Networks & Smart Cities
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Reasoning under Uncertainty: Relational Probabilistic Models

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• User Modeling, Personalization and Recommendation: On-Device user modeling, personalization, and recommendation
• Security and Privacy: Large-scale security measurements

Abstract

Networked cybernetic and physical systems of the Internet of Things (IoT) immerse civilian and industrial infrastructures into an interconnected and dynamic web of hybrid and mobile devices. The key feature of such systems is the hybrid and tight coupling of mobile and pervasive discrete communications in a continuously evolving environment (discrete computations with predominant continuous dynamics). In the aim of ensuring the correctness and reliability of such heterogeneous infrastructures, we introduce the hybrid {pi}-calculus (HpC), to formally capture both mobility, pervasiveness and hybridisation in infrastructures where the network topology and its communicating entities evolve continuously in the physical world. The {pi}-calculus proposed by Robin Milner et al. is a process calculus that can model mobile communications and computations in a very elegant manner. The HpC we propose is a conservative extension of the classical {pi}-calculus, i.e., the extension is ``minimal'', and yet describes mobility, time and physics of systems, while allowing to lift all theoretical results (e.g. bisimulation) to the context of that extension. We showcase the HpC by considering a realistic handover protocol among mobile devices.

Problem

• IoT network stability
• dynamic environmental changes
• device communication variability

Innovation

• Hybrid Pi Calculus
• Dynamic System Analysis
• Internet of Things (IoT)