No abstract

No abstract

We show that classical integrable models of last passage percolation and the related nonintersecting random walks converge uniformly on compact sets to the Airy line ensemble. Our core approach is to show convergence of nonintersecting Bernoulli random walks in all feasible directions in the parameter space. We then use coupling arguments to extend convergence to other models.

Scenario-based approaches have been receiving a huge amount of attention in research and engineering of automated driving systems. Due to the complexity and uncertainty of the driving environment, and the complexity of the driving task itself, the number of possible driving scenarios that an Automated Driving System or Advanced Driving-Assistance System may encounter is virtually infinite. Therefore it is essential to be able to reason about the identification of scenarios and in particular critical ones that may impose unacceptable risk if not considered. Critical scenarios are particularly important to support design, verification and validation efforts, and as a basis for a safety case. In this paper, we present the results of a systematic mapping study in the context of autonomous driving. The main contributions are: (i) introducing a comprehensive taxonomy for critical scenario identification methods; (ii) giving an overview of the state-of-the-art research based on the taxonomy encompassing 86 papers between 2017 and 2020; and (iii) identifying open issues and directions for further research. The provided taxonomy comprises three main perspectives encompassing the problem definition (the why), the solution (the methods to derive scenarios), and the assessment of the established scenarios. In addition, we discuss open research issues considering the perspectives of coverage, practicability, and scenario space explosion.

In this paper, we compare the performance of a genetic algorithm for test parameter optimization with simulated annealing and random testing. Simulated annealing and genetic algorithm both represent search-based testing strategies. In the context of autonomous and automated driving, we apply these methods to iteratively optimize test parameters, to aim at obtaining critical scenarios that form the basis for virtual verication and validation of Advanced Driver Assistant System (ADAS). We consider a test scenario to be critical if the underlying parameter set causes a malfunction of the system equipped with the ADAS function (i.e., near-crash or crash of the vehicle). To assess the criticality of each test scenario we rely on time-to-collision (TTC), which is a well-known and often used time-based safety indicator for recognizing rear-end conicts. For evaluating the performance of each testing strategy, we set up a simulation framework, where we automatically run simulations for each approach until a predened minimal TTC threshold is reached or a maximal number of iterations has passed. The genetic algorithm-based approach showed the best performance by generating critical scenarios with the lowest number of required test executions, compared to random testing and simulated annealing. Keywords: Autonomous vehicles • Genetic algorithm • Simulated annealing • System verication • Automatic testing.