Autonomous driving systems (ADSs) are complex cyber-physical systems (CPSs) that must ensure safety even in uncertain conditions. Modern ADSs often employ deep neural networks (DNNs), which may not produce correct results in every possible driving scenario. Thus, an approach to estimate the confidence of an ADS at runtime is necessary to prevent potentially dangerous situations. In this article we propose MarMot , an online monitoring approach for ADSs based on metamorphic relations (MRs), which are properties of a system that hold among multiple inputs and the corresponding outputs. Using domain-specific MRs, MarMot estimates the uncertainty of the ADS at runtime, allowing the identification of anomalous situations that are likely to cause a faulty behavior of the ADS, such as driving off the road. We perform an empirical assessment of MarMot with five different MRs, using two different subject ADSs, including a small-scale physical ADS and a simulated ADS. Our evaluation encompasses the identification of both external anomalies, e.g., fog, as well as internal anomalies, e.g., faulty DNNs due to mislabeled training data. Our results show that MarMot can identify up to 65% of the external anomalies and 100% of the internal anomalies in the physical ADS, and up to 54% of the external anomalies and 88% of the internal anomalies in the simulated ADS. With these results, MarMot outperforms or is comparable to other state-of-the-art approaches, including SelfOracle, Ensemble, and MC Dropout-based ADS monitors.

Cyber-Physical Systems (CPSs) combine digital cyber technologies with physical processes. As in any other software system, in the case of CPSs, the use of Artificial Intelligence (AI) techniques in general, and Deep Neural Networks (DNNs) in particular, is contantly increasing. While recent studies have considerably advanced the field of testing AI-enabled systems, it has not yet been investigated how different Deep Learning (DL) bugs affect AI-enabled CPSs in operation. This work-in-progress paper presents a preliminary evaluation on how such bugs can affect CPSs in operation by using a mobile robot as a case study system. For that, we generated DL mutants by using operators proposed by Humbatova et al., which are operators based on real-world DL faults. Our preliminary investigation suggests that such bugs are more difficult to detect when they are deployed in operation rather than when testing their DNN in an off-line setup, which contrast with related studies.

Programmable Logic Controllers (PLCs) are the core unit of the production system, which frequently need to implement new processes to address customer needs. These changes must be fully tested to ensure the reliability of the PLC code, which is commonly programmed through Functional Block Diagrams (FBDs). This is a tedious task that requires considerable time and effort given the manual nature of the process involved in PLC testing. Hence, we present a cost-effective test selection approach to test FBD programs in dynamic environments. The proposed method uses a search-based multi-objective test case selection algorithm as a regression technique to test recently modified FBD programs. Specifically, we derived a total of 7 fitness function combinations, by combining different cost and quality-based fitness functions. We carried out an empirical evaluation, by employing fitness metrics in the wellknown NSGA-II algorithm to determine the best configuration setup for testing FBD programs. Furthermore, we benchmarked the performance of the NSGA-II with the baseline Random Search (RS). The study was carried out with three case studies of a reactor protection system, and evaluated with two sets of mutants. The results demonstrated that the proposed approach significantly reduces time, while keeping high the overall fault detection capability.

Microservice Architectures have increasingly become popular in Industry 4.0 as they allow heterogeneous systems to interact, reduce the complexity in the management of individual components, and support distributed deployments. The integration of those distributed services into orchestrated production processes is performed by workflow managers. Next generation workflow managers must overcome a number of challenges when operating in microservice architectures and IoT environments. To overcome these challenges (heterogeneity, high dynamism, edge deployment or scalability), we propose a workflow manager alternative built in Node-RED. Node-RED provides instruments for the development of IoT systems and leverages the edge computing paradigm. This solution is deployable in embedded systems, is able to load and execute business processes by means of BPMN recipes and enables the integration of other frameworks and architectures.

Abstract The software of systems of elevators needs constant maintenance to deal with new functionality, bug fixes, or legislation changes. To automatically validate the software of these systems, a typical approach in industry is to use regression oracles, which execute test inputs both in the software version under test and in a previous software version. However, these practices require a long test execution time and cannot be re‐used at different test phases. To deal with these issues, we propose Dispatching AlgoRIthm Oracle (DARIO), a test oracle that relies on regression machine‐learning algorithms to detect both functional and non‐functional problems of the system. The machine‐learning algorithms of this oracle are trained by using data from previously tested versions to predict reference functional and non‐functional performance values of the new versions. An empirical evaluation with an industrial case study demonstrates the feasibility of using our approach. A total of five regression learning algorithms were validated by using mutation testing techniques. For the context of functional bugs, the accuracy when predicting verdicts by DARIO ranged between 95% and 98%, across the different scenarios proposed. For the context of non‐functional bugs, were competitive too, having an accuracy when predicting verdicts by DARIO ranged between 83% and 87%.

The software of elevators requires maintenance over several years to deal with new functionality, correction of bugs or legislation changes. To automatically validate this software, test oracles are necessary. A typical approach in industry is to use regression oracles. These oracles have to execute the test input both, in the software version under test and in a previous software version. This practice has several issues when using simulation to test elevators dispatching algorithms at system level. These issues include a long test execution time and the impossibility of re-using test oracles both at different test levels and in operation. To deal with these issues, we propose DARIO, a test oracle that relies on regression learning algorithms to predict the Qualify of Service of the system. The regression learning algorithms of this oracle are trained by using data from previously tested versions. An empirical evaluation with an industrial case study demonstrates the feasibility of using our approach in practice. A total of five regression learning algorithms were validated, showing that the regression tree algorithm performed best. For the regression tree algorithm, the accuracy when predicting verdicts by DARIO ranged between 79 to 87%.

Immersed in the digital era and fully experiencing the changes introduced by the new industrial revolution of the so-called Industry 4.0, there are still many aspects of industrial digitization to resolve. Interoperability among devices and machines is one of the challenges. Sensors, components and machines from different vendors work as independent silos offering large amounts of heterogeneous data which relational capabilities are not fully exploited. Quick development, deployment and testing of new software solutions that take advantage of those data is another important matter. The requirements in terms of equipment resources and engineering efforts is high when planning new implementations. Platforms that enable the efficient application of those solutions at the right level (machine, edge, plant or cloud) are also necessary.(p)(/p)This paper presents an industrial case study on the application of the Arrowhead framework. The framework is implemented in the Machine Tooling ecosystem and enables the integration of grinding machines with other sensors, components or machines. Different software engineering tools offered with Arrowhead are used to design new solutions in Cyber-Physical System and Internet of Things in Industry 4.0 and make them Arrowhead compliant, for fast deployment of platforms and applications (Dockers) or for testing purposes (Management tool). Finally, the potential of agile construction of new applications is analysed by providing an Human-Machine Interface at machine level and the provision of services for data consumption at cloud level.