Search results for "optimal"

Sleep Apnea, Sleepiness, and Driving Risk

2019

Obstructive sleep apnea is associated with excessive daytime sleepiness in about 50% of cases, and with increased risk of driving accidents. Treatment with continuous positive airway pressure effectively decreases such risk, but compliance with continuous positive airway pressure treatment is often suboptimal. According to the European Union Directive on driving risk, retention of a driving license in patients with obstructive sleep apnea requires assessment of sleepiness and adherence to continuous positive airway pressure treatment, but there remains uncertainty on the optimal methods to assess sleepiness on a large scale.

Religious spaces as continually evolving modernities: Forms of encounter with modernity in Christian Orthodoxy and Islam

2022

The present study deals with the encounter with modernity in two neighbouring religious spaces: Christian Orthodoxy and Islam. Relying on Eisenstadt’s theory about multiple modernities and on its further developments by Thomas Mergel and Kristina Stoeckl, Islamic and Christian-Orthodox dynamics in relation to the challenges of modernity are examined under two aspects: first, the decoupling between religion and culture as elaborated by Olivier Roy, and second, the development of modernist and fundamentalist currents as phenomena of modernity. The study contributes to the sketching of the profile of Islamic and the Christian-Orthodox modernities, pointing both to some of the commonalities and…

Autonomous Operation of Stationary Battery Energy Storage Systems—Optimal Storage Design and Economic Potential

2021

Global warming requires a changeover from fossil fuel based to renewable energy sources on the electrical supply side and electrification of the demand side. Due to the transient nature of renewables and fluctuating demand, buffer capacities are necessary to compensate for supply/demand imbalances. Battery energy storage systems are promising. However, the initial costs are high. Repurposing electric vehicle batteries can reduce initial costs. Further, storage design optimization could significantly improve costs. Therefore, a battery control algorithm was developed, and a simulation study was performed to identify the optimal storage design and its economic potential. The algorithm used is…

On incorporating the paradigms of discretization and Bayesian estimation to create a new family of pursuit learning automata

2013

Published version of an article in the journal: Applied Intelligence. Also available from the publisher at: http://dx.doi.org/10.1007/s10489-013-0424-x There are currently two fundamental paradigms that have been used to enhance the convergence speed of Learning Automata (LA). The first involves the concept of utilizing the estimates of the reward probabilities, while the second involves discretizing the probability space in which the LA operates. This paper demonstrates how both of these can be simultaneously utilized, and in particular, by using the family of Bayesian estimates that have been proven to have distinct advantages over their maximum likelihood counterparts. The success of LA-…

Solving two‐armed Bernoulli bandit problems using a Bayesian learning automaton

2010

PurposeThe two‐armed Bernoulli bandit (TABB) problem is a classical optimization problem where an agent sequentially pulls one of two arms attached to a gambling machine, with each pull resulting either in a reward or a penalty. The reward probabilities of each arm are unknown, and thus one must balance between exploiting existing knowledge about the arms, and obtaining new information. The purpose of this paper is to report research into a completely new family of solution schemes for the TABB problem: the Bayesian learning automaton (BLA) family.Design/methodology/approachAlthough computationally intractable in many cases, Bayesian methods provide a standard for optimal decision making. B…

PSA and PSA Kinetics Thresholds for the Presence of 68Ga-PSMA-11 PET/CT-Detectable Lesions in Patients with Biochemical Recurrent Prostate Cancer

2020

68Ga-PSMA-11 positron-emission tomography/computed tomography (PET/CT) is commonly used for restaging recurrent prostate cancer (PC) in European clinical practice. The goal of this study is to determine the optimum time for performing these PET/CT scans in a large cohort of patients by identifying the prostate-specific-antigen (PSA) and PSA kinetics thresholds for detecting and localizing recurrent PC. This retrospective analysis includes 581 patients with biochemical recurrence (BC) by definition. The performance of 68Ga-PSMA-11 PET/CT in relation to the PSA value at the scan time as well as PSA kinetics was assessed by the receiver-operating-characteristic-curve (ROC) generated by plottin…

Optimal Control of the Controlled Lotka-Volterra Equations with Applications - The Permanent Case

2022

In this article motivated by the control of complex microbiota in view to reduce the infection by a pathogenic agent, we introduce the theoretical frame from optimal control to analyze the problem. Two complementary approaches can be applied in the analysis: one is the so-called permanent case, where no digital constraints are concerning the control (taken as a measurable mapping) versus the sampled-data control case taking into account the logistic constraints, e.g. frequency of the medical interventions. The model is the n-dimensional Lotka-Volterra equation controlled using either probiotics or antibiotic agents or transplantation and bactericides. In the permanent case the Maximum princ…

Assessment of Granger causality by nonlinear model identification: application to short-term cardiovascular variability.

2007

A method for assessing Granger causal relationships in bivariate time series, based on nonlinear autoregressive (NAR) and nonlinear autoregressive exogenous (NARX) models is presented. The method evaluates bilateral interactions between two time series by quantifying the predictability improvement (PI) of the output time series when the dynamics associated with the input time series are included, i.e., moving from NAR to NARX prediction. The NARX model identification was performed by the optimal parameter search (OPS) algorithm, and its results were compared to the least-squares method to determine the most appropriate method to be used for experimental data. The statistical significance of…

Active Single-Blade Installation Using Tugger Line Tension Control and Optimal Control Allocation

2020

Ancillary Services in the Energy Blockchain for Microgrids

2019

The energy blockchain is a distributed Internet protocol for energy transactions between nodes of a power system. Recent applications of the energy blockchain in microgrids only consider the energy transactions between peers without considering the technical issues that can arise, especially when the system is islanded. One contribution of the paper is, thus, to depict a comprehensive framework of the technical and economic management of microgrids in the blockchain era, considering, for the first time, the provision of ancillary services and, in particular, of the voltage regulation service. When more PV nodes are operating in the grid, large reactive power flows may appear in the branches…