Data-driven inversion-based control of nonlinear systems

In this paper, we introduce the Data-Driven Inversion-Based Control (D2-IBC) method for nonlinear control system design. The method relies on a two degree-of-freedom architecture, with a nonlinear controller and a linear controller running in parallel, and does not require any detailed physical knowledge of the plant to control. Specically, we use input/output data to synthesize the control action by employing convex optimization tools only. We show the eectiveness of the proposed approach on a simulation example, where the D2-IBC performance is also compared to that of the Direct FeedbacK (DFK) design approach, a benchmark method for nonlinear controller design from data

A data-driven approach to nonlinear braking control

In modern road vehicles, active braking control systems are crucial elements to ensure safety and lateral stability. Unfortunately, the wheel slip dynamics is highly nonlinear and the on-line estimation of the road-tire conditions is still a challenging open research problem. These facts make it difficult to devise a braking control system that is reliable in any situation without being too conservative. In this paper, we propose the Data-Driven Inversion Based Control (D2-IBC) approach to overcome the above issues. The method relies on a two degrees of freedom architecture, with a linear controller and a nonlinear controller in parallel, both designed using only experimental data. The effectiveness of the proposed approach is shown by means of an extensive simulation campaign

Recent advances in the particle finite element method. Towards more complex fluid flow applications

One of the main drawbacks of the explicit integration using Eulerian formulations is the restricted stability of the solution with the time steps and with the spatial discretization. For the case of the Navier-Stokes equations, it is well known that the time step to be used in the solution is stable only for time step smaller than two critical values: the Courant- Friedrichs-Lewy (CFL) number and the Fourier number. The first one is concerning with the convective terms and the second one with the diffusive ones. Both numbers must be less than one to have stable algorithms. For convection dominant problems like high Reynolds number flows, the condition CFL<1 becomes crucial and limit the use of explicit method or outdistance it to be efficient. On the other hand, implicit solutions using Eulerian formulations is restricted in the time step size due to the lack of convergence of the convective non-linear terms. Both time integrations, explicit or implicit are, in most cases, limited to CFL no much larger than one. The possibility to perform parallel processing and the recent upcoming of new processors like GPU and GPGPU increase the possibilities of the explicit integration in time due to the facility to parallelize explicit methods having results with speedup closed to one. Although the incompressible condition cannot be solved explicitly, the solution of the momentum conservation equations with an explicit integration of the convective terms together with a parallel processing reduces considerably the computing time to solve the whole problem provided that a large time-step may be preserved independently to the discretization in space. Only to remember the new Particle Finite Element Method, called PFEM 2nd generation (PFEM-2) uses a Lagrangian formulation with an explicit time integrator without the CFL<1 restriction for the convective terms. This allows large timesteps, independent of the spatial discretization, having equal or better precision that an implicit integration. Moreover, PFEM-2 has two versions, one for moving mesh with permanent remeshing and one for fixed mesh [1]. In this lecture we will present some recent advances in the Particle Finite Element Method (PFEM) to solve the incompressible Navier- Stokes equations coupled with another fields like in multiphysics exploiting some nice features found in the fixed version. On the other hand we will also present the moving mesh version applied to multifluids using a parallel remeshing that makes this efficient in terms of cpu time. This updated proposal will be tested numerically and compared in terms of accuracy as in computing cpu time with other more standard Eulerian formulations

Increase in newly diagnosed type 1 diabetes and serological evidence of recent SARS-CoV-2 infection: Is there a connection?

Several studies have investigated the correlation between the COVID-19 pandemic and the onset of type 1 diabetes (T1D) in children, reporting an increased incidence of T1D and severe diabetic ketoacidosis (DKA). This study aimed to investigate the infection by SARS-CoV-2 in children with newly-diagnosed T1D to explore a possible link between SARS-CoV-2 infection, T1D and DKA. Thirty-nine children with a T1D new onset between October 15, 2020, and April 15, 2021, were enrolled. SARS-CoV-2 infection was investigated through a polymerase chain reaction on the nasal swab, dosage of specific antibodies, and an anamnestic question form. Nine (23%) of them had antibodies directed toward SARS-CoV-2, and five (12%) had a history of recent SARS-CoV-2 infection in themselves or in their family. No molecular swabs were positive. Compared to the general pediatric population, the overall incidence of COVID-19 was 5.6 times higher in the T1D patients' group (p < 0.00001). Referring only to the cases in the metropolitan area, we find a net increase in the incidence of T1D compared to the 5 years preceding our study, by 50% compared to the same months in 2016/2017 and 2017/2018, by 69% compared to 2018/2019 and by 77% compared to 2019/2020. The same trend was observed regarding DKA cases. The attributable risk of the pandemic cohort compared to the previous year is 44%. The abnormal disproportion of SARS-CoV-2 infection between children with T1D and the pediatric reference population, with a ratio of 5.6, appears to support the causative role of SARS-CoV-2 in triggering the immune response underlying diabetes, as often described for other viral infections. The difficulty accessing care services during the pandemic, with a consequent diagnosis delay, does not justify the increase in observed T1D cases, which could to be directly linked to the pandemic. The acceleration of the immune process provoked by SARS-CoV-2 may play a suggestive role in the development of T1D with DKA. Multicenter studies are needed to deepen and fully understand the pathophysiological link between SARS-CoV-2 and the onset of T1D in children

Tolterodine extended release in the treatment of male oab/storage luts: A systematic review

Overactive bladder (OAB)/ storage lower urinary tract symptoms (LUTS) have a high prevalence affecting up to 90\% of men over 80 years. The role of sufficient therapies appears crucial. In the present review, we analyzed the mechanism of action of tolterodine extended-release (ER) with the aim to clarify its efficacy and safety profile, as compared to other active treatments of OAB/storage LUTS.A wide Medline search was performed including the combination of following words: "LUTS", "BPH", "OAB", "antimuscarinic", "tolterodine", "tolterodine ER". IPSS, IPSS storage sub-score and IPSS QoL (International Prostate Symptom Score) were the validated efficacy outcomes. In addition, the numbers of urgency episodes/24 h, urgency incontinence episodes/24 h, incontinence episodes/24 h and pad use were considered. We also evaluated the most common adverse events (AEs) reported for tolterodine ER.Of 128 retrieved articles, 109 were excluded. The efficacy and tolerability of tolterodine ER Vs. tolterodine IR have been evaluated in a multicenter, double-blind, randomized placebo controlled study in 1529 patients with OAB. A 71\% mean reduction in urgency incontinence episodes was found in the tolterodine ER group compared to a 60\% reduction in the tolterodine IR (p 29 cc) only the combination therapy significantly reduced 24-h voiding frequency (2.8 vs. 1.7 with tamsulosin, 1.4 with tolterodine, or 1.6 with placebo). A recent meta-analysis evaluating tolterodine in comparison with other antimuscarinic drugs demonstrated that tolterodine ER was significantly more effective than placebo in reducing micturition/24 h, urinary leakage episodes/24 h, urgency episodes/24 h, and urgency incontinence episodes/24 h. With regard to adverse events, tolterodine ER was associated with a good adverse event profile resulting in the third most favorable antimuscarinic. Antimuscarinic drugs are the mainstay of pharmacological therapy for OAB / storage LUTS; several studies have demonstrated that tolterodine ER is an effective and well tolerated formulation of this class of treatment.Tolterodine ER resulted effective in reducing frequency urgency and nocturia and urinary leakage in male patients with OAB/storage LUTS. Dry mouth and constipation are the most frequently reported adverse events