Validating Multiple Variants of an Automotive Light System with Electrum

Abstract

This paper reports on the development and validation of a formal model for an automotive adaptive exterior lights system (ELS) with multiple variants in Electrum, a lightweight formal specification language that extends Alloy with mutable relations and temporal logic. We explore different strategies to address variability, one in pure Electrum and another through an annotative language extension. We then show how Electrum and its Analyzer can be used to validate systems of this nature, namely by checking that the reference scenarios are admissible, and to automatically verify whether the established requirements hold. A prototype was developed to translate the provided validation sequences into Electrum and back to further automate the validation process. The resulting ELS model was validated against the provided validation sequences and verified for most of requirements for all variants.

A journey with ASMETA from requirements to code: application to an automotive system with adaptive features

“…The approach by Cunha et al [29] adopts variants in Electrum, a lightweight formal specification language that extends Alloy with mutable relations and temporal logic to model the ELS subsystem. They explored different strategies to address variability, using pure Electrum and also an annotative language extension.…”

An automotive case study

“…The third contribution, "Validating Multiple Variants of an Automotive Light System with Alloy 6" by Cunha et al [4], presents an Alloy 6 model of the exterior light subsystem. Alloy 6 is the successor of Electrum and also supports mutable relations and LTL constraints.…”

Modeling with Mocking

“…ASMeta [21] 361 CarSystem001 Event-B [22] 455 M2 (not plain text, only lighting related lines) Classical-B [23] 363 Sensors, PitmanController_v6, PitmanController_TIME_v4, GenericTimers, BlinkLamps_v3 Electrum [24] 155 AdaptiveExteriorLight_EU (only lighting related lines) REBEL2 244 Actuators, Input, Sensors, Timer…”

“…Classical-B [23] Presented solution only addresses directional blinking and hazard warning lights. Electrum [24] No time management. All integer values are replace by enumerations.…”