Abstract
This paper introduces CARLA (spatially Constrained Anchor-based Recursive
Location Assignment), a recursive algorithm for assigning secondary or any
activity locations in activity-based travel models. CARLA minimizes distance
deviations while integrating location potentials, ensuring more realistic
activity distributions. The algorithm decomposes trip chains into smaller
subsegments, using geometric constraints and configurable heuristics to
efficiently search the solution space. Compared to a state-of-the-art
relaxation-discretization approach, CARLA achieves significantly lower mean
deviations, even under limited runtimes. It is robust to real-world data
inconsistencies, such as infeasible distances, and can flexibly adapt to
various priorities, such as emphasizing location attractiveness or distance
accuracy. CARLA's versatility and efficiency make it a valuable tool for
improving the spatial accuracy of activity-based travel models and agent-based
transport simulations. Our implementation is available at
https://github.com/tnoud/carla.
Loughborough University
Abstract
Artificial intelligence (AI) models are becoming key components in an
autonomous vehicle (AV), especially in handling complicated perception tasks.
However, closing the loop through AI-based feedback may pose significant risks
on reliability of autonomous driving due to very limited understanding about
the mechanism of AI-driven perception processes. To overcome it, this paper
aims to develop tools for modeling, analysis, and synthesis for a class of
AI-based AV; in particular, their closed-loop properties, e.g., stability,
robustness, and performance, are rigorously studied in the statistical sense.
First, we provide a novel modeling means for the AI-driven perception processes
by looking at their error characteristics. Specifically, three fundamental
AI-induced perception uncertainties are recognized and modeled by Markov
chains, Gaussian processes, and bounded disturbances, respectively. By means of
that, the closed-loop stochastic stability (SS) is established in the sense of
mean square, and then, an SS control synthesis method is presented within the
framework of linear matrix inequalities (LMIs). Besides the SS properties, the
robustness and performance of AI-based AVs are discussed in terms of a
stochastic guaranteed cost, and criteria are given to test the robustness level
of an AV when in the presence of AI-induced uncertainties. Furthermore, the
stochastic optimal guaranteed cost control is investigated, and an efficient
design procedure is developed innovatively based on LMI techniques and convex
optimization. Finally, to illustrate the effectiveness, the developed results
are applied to an example of car following control, along with extensive
simulation.
AI Insights - Stochastic guaranteed costs are introduced as a new metric to quantify robustness and passenger comfort under perception uncertainty.
- Explicitly modeling misdetection as a Markov jump process lets the LMI‑based controller dramatically boost reliability in adverse sensing.
- Car‑following experiments show the method reduces collision risk while keeping ride smoothness, proving a balance of safety and comfort.
- A noted weakness is the assumption of perfect perception‑uncertainty knowledge, suggesting future work on online estimation.
- The review highlights perception‑aware MPC and chance‑constrained stochastic MPC as complementary tools worth exploring.