Search results for "optimal"
showing 10 items of 706 documents
Periodic Controls in Step 2 Strictly Convex Sub-Finsler Problems
2020
We consider control-linear left-invariant time-optimal problems on step 2 Carnot groups with a strictly convex set of control parameters (in particular, sub-Finsler problems). We describe all Casimirs linear in momenta on the dual of the Lie algebra. In the case of rank 3 Lie groups we describe the symplectic foliation on the dual of the Lie algebra. On this basis we show that extremal controls are either constant or periodic. Some related results for other Carnot groups are presented. peerReviewed
Design of a robust controller for DC/DC converter–electrolyzer systems supplied by μWECSs subject to highly fluctuating wind speed
2020
Abstract A buck-based, isolated, high-voltage-ratio DC/DC converter that allows supplying a proton exchange membrane (PEM) electrolyzer from a micro-wind energy conversion system ( μ WECS) has been recently presented. It exhibits low ripple at the switching frequency on the output voltage and current and represents an attractive solution for low-cost hydrogen production. In this paper, a more accurate mathematical model of such a converter is derived and discussed. Then, a model-based robust controller is designed in the frequency domain using the Internal Model Control structure and in the context of H 2 ∕ H ∞ optimal control. The controller satisfies the condition of robust stability and …
Crowd-Averse Robust Mean-Field Games: Approximation via State Space Extension
2016
We consider a population of dynamic agents, also referred to as players. The state of each player evolves according to a linear stochastic differential equation driven by a Brownian motion and under the influence of a control and an adversarial disturbance. Every player minimizes a cost functional which involves quadratic terms on state and control plus a cross-coupling mean-field term measuring the congestion resulting from the collective behavior, which motivates the term “crowd-averse.” Motivations for this model are analyzed and discussed in three main contexts: a stock market application, a production engineering example, and a dynamic demand management problem in power systems. For th…
Selection of time windows in the horizontal-to-vertical noise spectral ratio by means of cluster analysis
2016
The selection of the elementary analysis windows in continuous noise recordings for optimal estimation of the mean horizontal‐to‐vertical spectral ratio (HVSR) curve is generally performed by visual inspection of HVSR curves considered as functions of time. Starting from full‐length records, HVSR curves are determined in consecutive time windows of appropriate lengths. Time windows with HVSR curves that are anomalous on the basis of a simple visual inspection are generally ignored in the computation of the average HVSR curve. It is often very difficult to optimize the selection of time windows to be used for the calculation of the HVSR curve representative of a site. The use of nonobjective…
Sustainable growth and environmental catastrophes
2017
Abstract In the standard AK growth model we introduce the threat of an ecological catastrophe and study the consequences for the economic variables in the long-run. We extend the basic framework by considering two environmental externalities: the first one is local and gives account of the marginal damage from emissions flow; the second one is aggregate, or global, and relates to the extreme damage which may happen if the accumulated stock of pollutants is on the threshold of a worldwide catastrophe. In this context dominated by market failures, we focus on the socially optimal solution and the search of conditions for sustainability. We identify the efficient balanced growth path, which ma…
No long-term effect of a 2-days intervention on how to prepare homemade food, on toddlers’ skepticism for new food and intake of fruits and vegetable…
2017
Objective Optimal nutrition from early age reduces the risk of developing non-communicable diseases later in life. The aim of this study was to examine the long-term effect on toddlers’ fruit and vegetable intake and sweet beverages, and skepticism for new food, of a 2-days’ intervention on how to prepare homemade food for toddlers. Results The effect of the cooking intervention was evaluated by a randomized, controlled trial where 110 parents of 4–6 months old infants were included. Child diet and food skepticism were measured at 6, 15 and 24 months of age. There were no differences between the control and intervention group in the consumption of fruits and vegetables and intake of water o…
Macronutrient balance and micronutrient amounts through growth and development
2021
AbstractNutrition is essential for human growth, particularly in newborns and children. An optimal growth needs a correct diet, in order to ensure an adequate intake of macronutrients and micronutrients. Macronutrients are the compounds that humans consume in largest quantities, mainly classified in carbohydrates, proteins and fats. Micronutrients are instead introduced in small quantities, but they are required for an adequate growth in the pediatric age, especially zinc, iron, vitamin D and folic acid. In this manuscript we describe the most important macro and micronutrients for children’s growth.
A practical algorithmic approach to mature aggressive B cell lymphoma diagnosis in the double/triple hit era. Selecting cases, matching clinical bene…
2019
An accurate diagnosis of clinically distinct subgroups of aggressive mature B cell lymphomas is crucial for the choice of proper treatment. Presently, precise recognition of these disorders relies on the combination of morphological, immunophenotypical, and cytogenetic/molecular features. The diagnostic workup in such situations implies the application of costly and time-consuming analyses, which are not always required, since an intensified treatment option is reasonably reserved to fit patients. The Italian Group of Haematopathology proposes herein a practical algorithm for the diagnosis of aggressive mature B cell lymphomas based on a stepwise approach, aimed to select cases deserving mo…
Did you hear? Auditory prospective memory cues are more beneficial for autistic than for non-autistic children and adolescents
2021
Item does not contain fulltext Background: The transition from primary to secondary school is particularly difficult for autistic children, a transition underpinned by an increase in prospective memory (PM) demands. Aims: To better understand PM in autistic children of the relevant age range and its underlying processes, the current study investigated the impact of cue salience (distinctiveness) on PM in autistic and non-autistic children and adolescents. The study was unique in manipulating the visual and auditory salience of PM cues. Salient cues are assumed to put lower demands on executive control resources as compared to cues that blend in with the ongoing activity. Methods and procedu…
Destination engagement on Facebook: Time and seasonality
2019
Abstract This paper studies the influence of time frames (posting day and posting time) and seasonality (low, medium and high) on positive/negative engagement in a Destination Management Organization (DMO) on Facebook. A content analysis was carried out on 639 posts, 178,913 audience reactions to such posts and 5330 comments. These posts were shared 45,194 times by the audience. The data analysis (regression analyses with optimal scaling) suggests that the best times to post are at 8 am , 10 am , 2 pm and 5 pm ; Thursday and Saturday are the best days to post, and the period before summer (from January to June) are the best months. These results have implications for DMOs and National T…