Optimal Control with $L^{\infty}$ cost: incorporating peak minimization

Fuente: arXiv
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Main Authors: Dhiman, Madhu, Kavitha, Veeraruna, Hemachandra, Nandyala
Format: Preprint
Published: 2024
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author Dhiman, Madhu
Kavitha, Veeraruna
Hemachandra, Nandyala
author_facet Dhiman, Madhu
Kavitha, Veeraruna
Hemachandra, Nandyala
contents Inventory and queueing systems are often designed by controlling weighted combination of some time-averaged performance metrics (like cumulative holding, shortage, server-utilization or congestion costs); but real-world constraints, like fixed storage or limited waiting space, require attention to peak levels reached during the operating period. This work formulates such control problems, which are any arbitrary weighted combination of some integral cost terms and an L-infinity(peak-level) term. The resultant control problem does not fall into standard control framework, nor does it have standard solution in terms of some partial differential equations. We introduce an auxiliary state variable to track the instantaneous peak-levels, enabling reformulation into the classical framework. We then propose a smooth approximation to handle the resultant discontinuities, and show the existence of unique value function that uniquely solves the corresponding Hamilton-Jacobi-Bellman equation. We apply this framework to two key applications to obtain an optimal design that includes controlling the peak-levels. Surprisingly, the numerical results show peak inventory can be minimized with negligible revenue loss (under 6%); without considering peak-control, the peak levels were significantly higher. The peak-optimal policies for queueing-system can reduce peak-congestion by up to 27%, however, at the expense of higher cumulative-congestion costs. Thus, for inventory-control, the performance of the average-terms did not degrade much, while the same is not true for queueing-system. Hence, one would require a judiciously chosen weighted design of all the costs involved including the peak-levels for any application and such a design can now be derived numerically using the proposed framework.
format Preprint
id arxiv_https___arxiv_org_abs_2406_05526
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Optimal Control with $L^{\infty}$ cost: incorporating peak minimization
Dhiman, Madhu
Kavitha, Veeraruna
Hemachandra, Nandyala
Optimization and Control
Inventory and queueing systems are often designed by controlling weighted combination of some time-averaged performance metrics (like cumulative holding, shortage, server-utilization or congestion costs); but real-world constraints, like fixed storage or limited waiting space, require attention to peak levels reached during the operating period. This work formulates such control problems, which are any arbitrary weighted combination of some integral cost terms and an L-infinity(peak-level) term. The resultant control problem does not fall into standard control framework, nor does it have standard solution in terms of some partial differential equations. We introduce an auxiliary state variable to track the instantaneous peak-levels, enabling reformulation into the classical framework. We then propose a smooth approximation to handle the resultant discontinuities, and show the existence of unique value function that uniquely solves the corresponding Hamilton-Jacobi-Bellman equation. We apply this framework to two key applications to obtain an optimal design that includes controlling the peak-levels. Surprisingly, the numerical results show peak inventory can be minimized with negligible revenue loss (under 6%); without considering peak-control, the peak levels were significantly higher. The peak-optimal policies for queueing-system can reduce peak-congestion by up to 27%, however, at the expense of higher cumulative-congestion costs. Thus, for inventory-control, the performance of the average-terms did not degrade much, while the same is not true for queueing-system. Hence, one would require a judiciously chosen weighted design of all the costs involved including the peak-levels for any application and such a design can now be derived numerically using the proposed framework.
title Optimal Control with $L^{\infty}$ cost: incorporating peak minimization
topic Optimization and Control
url https://arxiv.org/abs/2406.05526