2,792 research outputs found
The True Destination of EGO is Multi-local Optimization
Efficient global optimization is a popular algorithm for the optimization of
expensive multimodal black-box functions. One important reason for its
popularity is its theoretical foundation of global convergence. However, as the
budgets in expensive optimization are very small, the asymptotic properties
only play a minor role and the algorithm sometimes comes off badly in
experimental comparisons. Many alternative variants have therefore been
proposed over the years. In this work, we show experimentally that the
algorithm instead has its strength in a setting where multiple optima are to be
identified
AutonoVi: Autonomous Vehicle Planning with Dynamic Maneuvers and Traffic Constraints
We present AutonoVi:, a novel algorithm for autonomous vehicle navigation
that supports dynamic maneuvers and satisfies traffic constraints and norms.
Our approach is based on optimization-based maneuver planning that supports
dynamic lane-changes, swerving, and braking in all traffic scenarios and guides
the vehicle to its goal position. We take into account various traffic
constraints, including collision avoidance with other vehicles, pedestrians,
and cyclists using control velocity obstacles. We use a data-driven approach to
model the vehicle dynamics for control and collision avoidance. Furthermore,
our trajectory computation algorithm takes into account traffic rules and
behaviors, such as stopping at intersections and stoplights, based on an
arc-spline representation. We have evaluated our algorithm in a simulated
environment and tested its interactive performance in urban and highway driving
scenarios with tens of vehicles, pedestrians, and cyclists. These scenarios
include jaywalking pedestrians, sudden stops from high speeds, safely passing
cyclists, a vehicle suddenly swerving into the roadway, and high-density
traffic where the vehicle must change lanes to progress more effectively.Comment: 9 pages, 6 figure
A Tutorial on Bayesian Optimization of Expensive Cost Functions, with Application to Active User Modeling and Hierarchical Reinforcement Learning
We present a tutorial on Bayesian optimization, a method of finding the
maximum of expensive cost functions. Bayesian optimization employs the Bayesian
technique of setting a prior over the objective function and combining it with
evidence to get a posterior function. This permits a utility-based selection of
the next observation to make on the objective function, which must take into
account both exploration (sampling from areas of high uncertainty) and
exploitation (sampling areas likely to offer improvement over the current best
observation). We also present two detailed extensions of Bayesian optimization,
with experiments---active user modelling with preferences, and hierarchical
reinforcement learning---and a discussion of the pros and cons of Bayesian
optimization based on our experiences
CAT: Closed-loop Adversarial Training for Safe End-to-End Driving
Driving safety is a top priority for autonomous vehicles. Orthogonal to prior
work handling accident-prone traffic events by algorithm designs at the policy
level, we investigate a Closed-loop Adversarial Training (CAT) framework for
safe end-to-end driving in this paper through the lens of environment
augmentation. CAT aims to continuously improve the safety of driving agents by
training the agent on safety-critical scenarios that are dynamically generated
over time. A novel resampling technique is developed to turn log-replay
real-world driving scenarios into safety-critical ones via probabilistic
factorization, where the adversarial traffic generation is modeled as the
multiplication of standard motion prediction sub-problems. Consequently, CAT
can launch more efficient physical attacks compared to existing safety-critical
scenario generation methods and yields a significantly less computational cost
in the iterative learning pipeline. We incorporate CAT into the MetaDrive
simulator and validate our approach on hundreds of driving scenarios imported
from real-world driving datasets. Experimental results demonstrate that CAT can
effectively generate adversarial scenarios countering the agent being trained.
After training, the agent can achieve superior driving safety in both
log-replay and safety-critical traffic scenarios on the held-out test set. Code
and data are available at https://metadriverse.github.io/cat.Comment: 7th Conference on Robot Learning (CoRL 2023
Predicting links in ego-networks using temporal information
Link prediction appears as a central problem of network science, as it calls
for unfolding the mechanisms that govern the micro-dynamics of the network. In
this work, we are interested in ego-networks, that is the mere information of
interactions of a node to its neighbors, in the context of social
relationships. As the structural information is very poor, we rely on another
source of information to predict links among egos' neighbors: the timing of
interactions. We define several features to capture different kinds of temporal
information and apply machine learning methods to combine these various
features and improve the quality of the prediction. We demonstrate the
efficiency of this temporal approach on a cellphone interaction dataset,
pointing out features which prove themselves to perform well in this context,
in particular the temporal profile of interactions and elapsed time between
contacts.Comment: submitted to EPJ Data Scienc
An Information-Theoretic Approach for Estimating Scenario Generalization in Crowd Motion Prediction
Learning-based approaches to modeling crowd motion have become increasingly
successful but require training and evaluation on large datasets, coupled with
complex model selection and parameter tuning. To circumvent this tremendously
time-consuming process, we propose a novel scoring method, which characterizes
generalization of models trained on source crowd scenarios and applied to
target crowd scenarios using a training-free, model-agnostic Interaction +
Diversity Quantification score, ISDQ. The Interaction component aims to
characterize the difficulty of scenario domains, while the diversity of a
scenario domain is captured in the Diversity score. Both scores can be computed
in a computation tractable manner. Our experimental results validate the
efficacy of the proposed method on several simulated and real-world
(source,target) generalization tasks, demonstrating its potential to select
optimal domain pairs before training and testing a model
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