Modeling and debugging numerical constraints of cyber-physical systems design

Abstract

To design and analyze Cyber-Physical Systems (CPSs), engineers should consider computation and physical processes at the same time. Engineers require a design description which is easy to understand. SysML provides diagrammatic notations which are independent of specific disciplines. To express numerical constraints of SysML diagrams, we extend OCL with real arithmetic. Both SysML and extended-OCL require an executable design language to check inconsistencies of constraints. To achieve the above idea, we bridge a gap between SysML and VDM-RT. We propose a framework to embed SysML/extended-OCL into VDM-RT, where we prepare some libraries for extended-OCL. It is unnecessary for engineers to know VDM-RT. Using a unified CPS design description, our approach automatically debugs inconsistencies in whole CPS design. This paper illustrates the proposed method with a car race system.

Giving a Model-Based Testing Language a Formal Semantics via Partial MAX-SAT

“…Mechtaev et al have devised a tool called DirectFix [18] for program repairs based on PMSAT or, more specifically, Partial MAX-SMT. Similarly to our approach, Tien et al [26] use PMSAT to find contradictory constraints in SysML models.…”

Design-time detection of physical-unit changes in product lines

“…A unit is a specific quantity, chosen by convention, used to express numerically quantities that have the same dimension Clifford (1985). Units exist in both design level and implementation Tien et al (2013). Worse yet is that many physical unit inconsistencies escape the testing into the deployed product.…”