Risk-averse optimization of total rewards in Markovian models using deviation measures

Fuente: arXiv
Salvato in:
Dettagli Bibliografici
Autori principali: Baier, Christel, Piribauer, Jakob, Starke, Maximilian
Natura: Preprint
Pubblicazione: 2024
Soggetti:
Accesso online:
Tags: Aggiungi Tag
Nessun Tag, puoi essere il primo ad aggiungerne!!
_version_ 1866913423255666688
author Baier, Christel
Piribauer, Jakob
Starke, Maximilian
author_facet Baier, Christel
Piribauer, Jakob
Starke, Maximilian
contents This paper addresses objectives tailored to the risk-averse optimization of accumulated rewards in Markov decision processes (MDPs). The studied objectives require maximizing the expected value of the accumulated rewards minus a penalty factor times a deviation measure of the resulting distribution of rewards. Using the variance in this penalty mechanism leads to the variance-penalized expectation (VPE) for which it is known that optimal schedulers have to minimize future expected rewards when a high amount of rewards has been accumulated. This behavior is undesirable as risk-averse behavior should keep the probability of particularly low outcomes low, but not discourage the accumulation of additional rewards on already good executions. The paper investigates the semi-variance, which only takes outcomes below the expected value into account, the mean absolute deviation (MAD), and the semi-MAD as alternative deviation measures. Furthermore, a penalty mechanism that penalizes outcomes below a fixed threshold is studied. For all of these objectives, the properties of optimal schedulers are specified and in particular the question whether these objectives overcome the problem observed for the VPE is answered. Further, the resulting algorithmic problems on MDPs and Markov chains are investigated.
format Preprint
id arxiv_https___arxiv_org_abs_2407_06887
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Risk-averse optimization of total rewards in Markovian models using deviation measures
Baier, Christel
Piribauer, Jakob
Starke, Maximilian
Logic in Computer Science
This paper addresses objectives tailored to the risk-averse optimization of accumulated rewards in Markov decision processes (MDPs). The studied objectives require maximizing the expected value of the accumulated rewards minus a penalty factor times a deviation measure of the resulting distribution of rewards. Using the variance in this penalty mechanism leads to the variance-penalized expectation (VPE) for which it is known that optimal schedulers have to minimize future expected rewards when a high amount of rewards has been accumulated. This behavior is undesirable as risk-averse behavior should keep the probability of particularly low outcomes low, but not discourage the accumulation of additional rewards on already good executions. The paper investigates the semi-variance, which only takes outcomes below the expected value into account, the mean absolute deviation (MAD), and the semi-MAD as alternative deviation measures. Furthermore, a penalty mechanism that penalizes outcomes below a fixed threshold is studied. For all of these objectives, the properties of optimal schedulers are specified and in particular the question whether these objectives overcome the problem observed for the VPE is answered. Further, the resulting algorithmic problems on MDPs and Markov chains are investigated.
title Risk-averse optimization of total rewards in Markovian models using deviation measures
topic Logic in Computer Science
url https://arxiv.org/abs/2407.06887