Aren A. Babikian

Aren A. Babikian, Alessio Di Sandro, Federico Formica et al.

The development of complex software systems, e.g., cyber-physical systems (CPSs), involves continuous evolution of both system implementations and their requirements. These two artifacts often proceed independently, creating a risk of misalignment. For example, a system may be updated due to implementation-level concerns, yielding a new version that no longer satisfies its original requirements. Traditional compliance recovery techniques, e.g., automated program repair, address this problem by modifying the system while assuming that requirements are correct. However, faulty, outdated or inadequate requirements are a well-documented challenge in practice, motivating the complementary task of requirement repair. In this paper, we propose a framework that leverages system execution data to repair misaligned CPS requirements, thereby restoring requirement-to-system compliance. Our approach evaluates the correctness of declarative requirements over time-based, real-valued signals expressed using the MATLAB Simulink Requirements Tables language. We evaluate seven variants of our framework on six real-world case studies covering 12 requirements. Results confirm the effectiveness of the proposed framework in producing correct and useful repaired requirements.

Boqi Chen, José Antonio Hernández López, Aren A. Babikian

Large language models (LLMs) are increasingly used to generate software artifacts across many software engineering (SE) tasks, yet ensuring the semantic validity of these artifacts remains a fundamental challenge. Existing constrained decoding techniques can enforce syntactic correctness and, in some cases, specific semantic rules, but lack a general representation that bridges LLM-generated text with the reasoning required for semantic validation in SE. In this paper, we propose projectional decoding, a novel conceptual framework that integrates domain semantics directly into the generation process by maintaining, alongside text, a partial graph model as the primary artifact representation throughout generation. This abstract representation enables incremental semantic validation by explicitly capturing uncertainty and natively supporting error detection, while guiding generation toward semantically valid outputs with provable guarantees. We present preliminary results on a program generation task which demonstrate the potential of this approach to improve the semantic validity of LLM-generated artifacts. We also discuss how projectional decoding can enable verifiable automation with LLMs across various SE activities.

Aren A. Babikian, Attila Ficsor, Oszkár Semeráth et al.

To ensure their safe use, autonomous vehicles (AVs) must meet rigorous certification criteria that involve executing maneuvers safely within (arbitrary) scenarios where other actors perform their intended maneuvers. For that purpose, existing scenario generation approaches optimize search to derive scenarios with high probability of dangerous situations. In this paper, we hypothesize that at road junctions, potential danger predominantly arises from overlapping paths of individual actors carrying out their designated high-level maneuvers. As a step towards AV certification, we propose an approach to derive a complete set of (potentially dangerous) abstract scenarios at any given road junction, i.e. all permutations of overlapping abstract paths assigned to actors (including the AV) for a given set of possible abstract paths. From these abstract scenarios, we derive exact paths that actors must follow to guide simulation-based testing towards potential collisions. We conduct extensive experiments to evaluate the behavior of a state-of-the-art learning-based AV controller on scenarios generated over two realistic road junctions with increasing number of external actors. Results show that the AV-under-test is involved in increasing percentages of unsafe behaviors in simulation, which vary according to functional- and logical-level scenario properties.