scholarly journals Multi-fidelity black-box optimization for time-optimal quadrotor maneuvers

2021 ◽  
pp. 027836492110333
Author(s):  
Gilhyun Ryou ◽  
Ezra Tal ◽  
Sertac Karaman
Keyword(s):  
Real World ◽  
High Speed ◽  
Analytical Approximation ◽  
Black Box ◽  
Bayesian Optimization ◽  
Optimization Framework ◽  
Quadrotor Aircraft ◽  
Time Optimal ◽  
Feasibility Constraints ◽  
Generation Problem

We consider the problem of generating a time-optimal quadrotor trajectory for highly maneuverable vehicles, such as quadrotor aircraft. The problem is challenging because the optimal trajectory is located on the boundary of the set of dynamically feasible trajectories. This boundary is hard to model as it involves limitations of the entire system, including complex aerodynamic and electromechanical phenomena, in agile high-speed flight. In this work, we propose a multi-fidelity Bayesian optimization framework that models the feasibility constraints based on analytical approximation, numerical simulation, and real-world flight experiments. By combining evaluations at different fidelities, trajectory time is optimized while the number of costly flight experiments is kept to a minimum. The algorithm is thoroughly evaluated for the trajectory generation problem in two different scenarios: (1) connecting predetermined waypoints; (2) planning in obstacle-rich environments. For each scenario, we conduct both simulation and real-world flight experiments at speeds up to 11 m/s. Resulting trajectories were found to be significantly faster than those obtained through minimum-snap trajectory planning.

From Monetary to Nonmonetary Mechanism Design via Artificial Currencies

2021 ◽  
Author(s):  
Artur Gorokh ◽  
Siddhartha Banerjee ◽  
Krishnamurthy Iyer
Keyword(s):  
Decision Making ◽  
Mechanism Design ◽  
Real World ◽  
Price Of Anarchy ◽  
Black Box ◽  
Trade Off ◽  
Two Agents ◽  
Over Time ◽  
Artificial Currency

Nonmonetary mechanisms for repeated allocation and decision making are gaining widespread use in many real-world settings. Our aim in this work is to study the performance and incentive properties of simple mechanisms based on artificial currencies in such settings. To this end, we make the following contributions: For a general allocation setting, we provide two black-box approaches to convert any one-shot monetary mechanism to a dynamic nonmonetary mechanism using an artificial currency that simultaneously guarantees vanishing gains from nontruthful reporting over time and vanishing losses in performance. The two mechanisms trade off between their applicability and their computational and informational requirements. Furthermore, for settings with two agents, we show that a particular artificial currency mechanism also results in a vanishing price of anarchy.

A Novel Approach for Deploying Minimum Sensors in Smart Buildings

2022 ◽  
Vol 6 (1) ◽  
pp. 1-29
Author(s):  
Anshul Agarwal ◽  
Krithi Ramamritham
Keyword(s):  
Real World ◽  
Cyber Physical Systems ◽  
Management Systems ◽  
Physical Systems ◽  
Optimization Framework ◽  
Sensing System ◽  
Novel Approach ◽  
Building Management ◽  
Minimum Number ◽  
Building Management Systems

Buildings, viewed as cyber-physical systems, become smart by deploying Building Management Systems (BMS). They should be aware about the state and environment of the building. This is achieved by developing a sensing system that senses different interesting factors of the building, called as “facets of sensing.” Depending on the application, different facets need to be sensed at various locations. Existing approaches for sensing these facets consist of deploying sensors at all the places so they can be sensed directly. But installing numerous sensors often aggravate the issues of user inconvenience, cost of installation and maintenance, and generation of e-waste. This article proposes how intelligently using the existing information can help to estimate the facets in cyber-physical systems like buildings, thereby reducing the sensors to be deployed. In this article, an optimization framework has been developed, which optimally deploys sensors in a building such that it satisfies BMS requirements with minimum number of sensors. The proposed solution is applied to real-world scenarios with cyber-physical systems. The results indicate that the proposed optimization framework is able to reduce the number of sensors by 59% and 49% when compared to the baseline and heuristic approach, respectively.

Practical Evaluation of Steady Flow Resulting from a Free-Surface Pressure Patch

2009 ◽  
Vol 53 (03) ◽  
pp. 137-150
Author(s):  
Francis Noblesse ◽  
Gérard Delhommeau ◽  
Chi Yang
Keyword(s):  
Free Surface ◽  
Surface Pressure ◽  
High Speed ◽  
Surface Effect ◽  
Practical Method ◽  
Analytical Approximation ◽  
Surface Boundary ◽  
Steady Flows ◽  
Local Flow ◽  
The Green Function

The linearized potential flow resulting from a distribution of pressure that advances at constant speed along a straight path at the free surface of calm water, of effectively infinite depth and lateral extent, is considered. A practical method for evaluating the free-surface elevation caused by the moving free-surface pressure patch—which can be used to model steady flows of air-cushion vehicles, high-speed planing boats, surface-effect ships, and some types of hybrid ships—is given. The key ingredient of this method is a highly simplified analytical approximation to the local-flow component in the expression for the Green function associated with the classic Michell-Kelvin linearized free-surface boundary condition.

scholarly journals Droplet microfluidics: from proof-of-concept to real-world utility?

2019 ◽  
Vol 55 (67) ◽  
pp. 9895-9903 ◽  
Author(s):  
Akkapol Suea-Ngam ◽  
Philip D. Howes ◽  
Monpichar Srisa-Art ◽  
Andrew J. deMello
Keyword(s):  
Real World ◽  
High Speed ◽  
Droplet Microfluidics ◽  
Proof Of Concept ◽  
Conventional Instrumentation ◽  
Practical Tool ◽  
Tool Set

Droplet microfluidics constitutes a diverse and practical tool set that enables chemical and biological experiments to be performed at high speed and with enhanced efficiency when compared to conventional instrumentation.

scholarly journals Plastic Zone Analysis of Deep-Buried, Noncircular Tunnel and Application on the High-Speed Railway in the Karst Area

2017 ◽  
Vol 2017 ◽  
pp. 1-10
Author(s):  
Hai Shi ◽  
Mingzhou Bai
Keyword(s):  
Plastic Zone ◽  
High Speed ◽  
Mapping Function ◽  
Analytical Approximation ◽  
Surrounding Rock ◽  
Karst Area ◽  
High Speed Railway ◽  
Strength Failure ◽  
Circular Unit ◽  
Safety Thickness

With the conformal mapping function provided by Verruijt, the outland of a noncircular tunnel can be mapped to a circular unit in the complex plane and then spread the analytic function into a Laurent series. The stress unified solution of oval and horseshoe cross section can be determined using Muskhelishvili’s complex variables function method. Subsequently, the solution can be taken into the Griffith strength failure criterion and determine the scale and shape of plastic zone in the tunnel surrounding rock. Aiming at the critical safety thickness between a concealed cave and tunnel in the karst area and determining whether the plastic zone of tunnel surrounding rock is connected with the plastic zone of cave as a judgment standard, the model of critical safety thickness among the concealed caves and tunnels is established. The numerical model is established in comparison with the computing method of rock plate critical safety thickness in actual engineering based on the Doumo tunnel engineering of Shanghai-Kunming (Guizhou segment) high-speed railway. The following conclusions can be drawn: the analytical approximation method has less indexes, and the output of this method is approximately close to actual engineering and numerical analysis, in which it is reliable and rational.

scholarly journals 3D Analysis of Low-Voltage Gas-Filled DC Switch Using Simplified Arc Model

2019 ◽  
Vol 6 (1) ◽  
pp. 65-68 ◽  
Author(s):  
S. Gortschakow ◽  
D. Gonzalez ◽  
S. Yu ◽  
F. Werner
Keyword(s):  
High Speed ◽  
Low Voltage ◽  
Black Box ◽  
Optical Observations ◽  
3D Analysis ◽  
High Speed Camera ◽  
Plasma Model ◽  
Arc Model ◽  
Arc Current ◽  
Electro Magnetic

Electro-magnetic simulations have been used for the visualization of distribution of Lorentz force acting on a DC switching arc in low-voltage contactor. A simplified plasma model (black-box model) was applied for the description of arc conductivity. Arc geometry was gained from the high-speed camera images. Influence of arc position, arc current and of external magnetic field has been studied. Results have been compared with optical observations of the arc dynamics.

scholarly journals Black-box combinatorial optimization using models with integer-valued minima

2020 ◽  
Author(s):  
Laurens Bliek ◽  
Sicco Verwer ◽  
Mathijs de Weerdt
Keyword(s):  
Optimization Algorithm ◽  
Surrogate Model ◽  
Optimization Problems ◽  
Random Search ◽  
Continuous Optimization ◽  
Optimal Solution ◽  
Black Box ◽  
Combinatorial Problems ◽  
Bayesian Optimization ◽  
Bayesian Optimization Algorithm

Abstract When a black-box optimization objective can only be evaluated with costly or noisy measurements, most standard optimization algorithms are unsuited to find the optimal solution. Specialized algorithms that deal with exactly this situation make use of surrogate models. These models are usually continuous and smooth, which is beneficial for continuous optimization problems, but not necessarily for combinatorial problems. However, by choosing the basis functions of the surrogate model in a certain way, we show that it can be guaranteed that the optimal solution of the surrogate model is integer. This approach outperforms random search, simulated annealing and a Bayesian optimization algorithm on the problem of finding robust routes for a noise-perturbed traveling salesman benchmark problem, with similar performance as another Bayesian optimization algorithm, and outperforms all compared algorithms on a convex binary optimization problem with a large number of variables.

scholarly journals Modelling human active search in optimizing black-box functions

2020 ◽  
Vol 24 (23) ◽  
pp. 17771-17785
Author(s):  
Antonio Candelieri ◽  
Riccardo Perego ◽  
Ilaria Giordani ◽  
Andrea Ponti ◽  
Francesco Archetti
Keyword(s):  
Active Learning ◽  
Bayesian Learning ◽  
Surrogate Models ◽  
Black Box ◽  
Bayesian Optimization ◽  
Learning Approaches ◽  
Function Learning ◽  
The Subject ◽  
Human Function ◽  
Exploration Exploitation

AbstractModelling human function learning has been the subject of intense research in cognitive sciences. The topic is relevant in black-box optimization where information about the objective and/or constraints is not available and must be learned through function evaluations. In this paper, we focus on the relation between the behaviour of humans searching for the maximum and the probabilistic model used in Bayesian optimization. As surrogate models of the unknown function, both Gaussian processes and random forest have been considered: the Bayesian learning paradigm is central in the development of active learning approaches balancing exploration/exploitation in uncertain conditions towards effective generalization in large decision spaces. In this paper, we analyse experimentally how Bayesian optimization compares to humans searching for the maximum of an unknown 2D function. A set of controlled experiments with 60 subjects, using both surrogate models, confirm that Bayesian optimization provides a general model to represent individual patterns of active learning in humans.

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