305,219 research outputs found
Giuseppe Schiassi commentatore della tragedia
No full textGiuseppe Schiassi fu un fine filologo testuale e un puntuale e intelligente commentatore della tragedia. Anche se legato alla cultura idealistica del suo tempo, il suo insegnamento presupponeva un'intima connessione tra cultura e lingua, che è tuttora attuale
Schiassi (G.). Sofocle, Le Trachinie, con introduzione e commento.
No full textDeman Alb. Schiassi (G.). Sofocle, Le Trachinie, con introduzione e commento.. In: Revue belge de philologie et d'histoire, tome 33, fasc. 2, 1955. pp. 357-359
Schiassi (G.). Sofocle, Le Trachinie, con introduzione e commento.
No full textDeman Alb. Schiassi (G.). Sofocle, Le Trachinie, con introduzione e commento.. In: Revue belge de philologie et d'histoire, tome 33, fasc. 2, 1955. pp. 357-359
Bellman neural networks for the class of optimal control problems with integral quadratic cost
No full textThis article introduces Bellman neural networks (BeNNs) and employs them to learn the optimal control actions for the class of optimal control problems (OCPs) with integral quadratic cost. BeNNs represent a particular family of physicsinformed neural networks specifically designed and trained to tackle OCPs via applying the Bellman principle of optimality (BPO). The BPO provides necessary and sufficient optimality conditions, which result in a nonlinear partial differential equation known as the Hamilton-Jacobi-Bellman (HJB) equation. BeNNs learn the optimal control actions from the unknown solution of the arising HJB equation (i.e., the value function), where the unknown solution is modeled using a neural network. In addition, this article shows how to estimate the upper bounds on the generalization error of BeNNs while learning the solutions for the OCP class under consideration. The generalization error estimate is provided in terms of the choice and number of the training points as well as the training error. Numerical studies show that BeNNs can be successfully applied to learn the feedback control actions for the class of OCPs considered and, after the training is completed, deployed to control the system in a closed-loop fashion. Impact Statement-The proposed research improves our understanding of how to solve optimal control problems with closed-loop solutions and has potentially a countless number of applications in several different areas. The study is at the intersection between optimal control theory and artificial intelligence connected with mathematical tools for functional interpolation. This advances the ability to implement a higher level of autonomy in decision-making for practical applications with a beneficial impact on our society
An Overview of X-TFC Applications for Aerospace Optimal Control Problems
No full textThis paper is an overview of Optimal Control Problems (OCPs) for aerospace applications tackled via the indirect method and a particular Physics-Informed Neural Networks (PINNs) framework, developed by the authors, named Extreme Theory of Functional Connections (X-TFC). X-TFC approximates the unknown OCP solutions via the Constrained Expressions, which are functionals made up of the sum of a free-function and a functional that analytically satisfies the boundary conditions. Thanks to this property, the framework is fast and accurate in learning the solution to the Two-Point Boundary Value Problem (TPBVP) arising after applying the Pontryagin Minimum Principle. The applications presented in this paper regard intercept problems, interplanetary planar orbit transfers, transfer trajectories within the Circular Restricted Three-Body Problem, and safe trajectories around asteroids with collision avoidance. The main results are presented and discussed, proving the efficiency of the proposed framework in solving OCPs and its low computational times, which can potentially enable a higher level of autonomy in decision-making for practical applications
Il chirurgo Benedetto Schiassi e la prima anestesia spinale in Italia (1899)
No full text“The surgeon Benedetto Schiassi and the first spinal anesthesia in Italy”. Recent research has allowed us to identify that it was the surgeon Benedetto Schiassi, known for the surgical procedure of vagotomy in the peptic ulcer, who performed the first spinal anesthesia in Italy: on December 27, 1899, at the Umberto and Margherita Hospital in Budrio, his birthplace. Four publications by Schiassi and the documentation in the archive of the Budrio Hospital attest to the execution of the surgical intervention with this anesthesia. It was carried out urgently in a 70-year-old man, suffering from gangrene of the right foot, in order to perform a leg amputation. He describes the clinical status of the patient characterized by diffuse arteriosclerosis, left ventricle dilatation and arrhythmia. His general clinical condition was so compromised that Schiassi considered general anesthesia extremely risky, which at the time was performed with ether or chloroform and was burdened with severe mortality if practiced in critically ill patients. The drug used was cocaine certainly considered the forefather of all local anesthetics. No other documents, scientific research or curricula pertaining to other Italian surgeons of the time have been found in the literature, to whom the execution of a spinal anesthesia could be attributed in a period prior to that performed by Schiassi. We believe it important to reconstruct the authorship of this anesthesia in Italy, underlining Benedetto Schiassi’s innovative vision in understanding the theoretical value and clinical utility of this anesthesiological method, still widely used today, which, on the occasion of its 125th anniversary, deserves to be remembered.Recenti ricerche hanno permesso di identificare che è stato il chirurgo Benedetto Schiassi, conosciuto per l’intervento chirurgico di vagotomia nell’ulcera peptica, ad eseguire la prima anestesia spinale in Italia il 27 dicembre 1899, presso l’Ospedale Umberto e Margherita di Budrio, sua città natale. Quattro sue pubblicazioni e la documentazione dell’archivio dell’Ospedale di Budrio attestano l’esecuzione dell’intervento chirurgico con tale tipo di anestesia. Fu effettuato d’urgenza ad un paziente di settant’anni, affetto da gangrena del piede destro, per eseguire l’amputazione della gamba. Lo stato clinico del paziente era caratterizzato da arteriosclerosi diffusa, dilatazione del ventricolo sinistro e aritmia. Le sue condizioni cliniche generali erano talmente compromesse che il chirurgo considerava estremamente rischioso praticare l’anestesia generale, all’epoca eseguita con etere o cloroformio somministrati per via inalatoria e gravata di elevata mortalità, se effettuata su pazienti critici. Il farmaco utilizzato fu la cocaina, considerata la progenitrice di tutti gli anestetici locali. Non sono stati recuperati in letteratura documenti, ricerche scientifiche o curricula riguardanti altri chirurghi italiani dell’epoca, ai quali si possa attribuire l’esecuzione di un’anestesia spinale in un periodo precedente a quella eseguita da Schiassi. Riteniamo importante avere ricostruito la paternità di questa anestesia in Italia, sottolineando la visione innovativa di Benedetto Schiassi nel comprendere il valore teorico e l’utilità clinica di tale metodica, ancora oggi ampiamente utilizzata, che, in occasione del suo 125° anniversario, merita di essere ricordat
L'Epitafio e gli ideali democratici di Lisia nella lettura di Giuseppe Schiassi
No full textAround 1960, Giuseppe Schiassi focussed his attention on the corpusculum of the Athenian speeches written for the public ceremony held every year in the Kerameikos in honor of the Athenian soldiers fallen in war. After his 1959 commentary on Hypereides’ Epitaph and an article on Plato’s Menexenos (1962), he published in 1962 a commentary on the Epitaph transmitted as or. II in the corpus Lysiacum. Following in the steps of J. Walz, F. Zucker and F. Buchner, he pleads for the authenticity of the speech, interpreting it as a mature document of Lysias’ loyalty to the traditional ideals of democratic Athens, enriched with new panhellenic ideas. Though sometimes too confident in the possibility to extract personal opinions from the writings of the logographs, the commentary sets in a honest and clear way the arguments in favour of Lysianic authorship and gives an articulated picture of the place of the speech in early fourth-century Athens’ politics. His work still deservers the attention of all scholars interested in Lysias’ oratory
Effetti dell'attività fisica e sportiva sulla prestazione motoria
No full textThe aim of the study was to analyse the conditional and coordinative motor performances in relation to physical activity and individual sports background in middle-school students.
201 boys and 220 girls students (age 11-12-13 years) from Bologna responded to a questionnaire on the type and volume of physical and sports activities practiced outside the school. The participants also performed a battery of conditional motor tests (standing long jump, seated throw, dash run) and coordinative tests ( balance, rhythm and precision), easy to carry out in a school context.
The majority of boys practiced Team Sports (SS ), while girls preferred Individual sports (SI ). In general, students practicing SS showed higher levels of physical and sports activity. The performances of boys in the tests were better than those of girls, with the exception of rhythm and precision tests, in which girls outperformed their peers.
Girls practicing SS showed better motor performances than girls practicing SI, while boys practicing SS showed better results than boys practicing SI only in throwing and running. In all the tests, the most active girls (> 160 h/year) showed better performances, compared to the less active ones . It can be concluded that high physical activity and sport volume lead to better physical performance, especially in girls. The more boys M performed better than less active boys only regarding coordination (speed and balance tests).
The study confirms the importance of educating motor coordination, using team and individual sports, as well as the importance of engaging students in extracurricular activities, in order to reach the minimum amount of physical activity recommended by the OMS
Physics-Informed Neural Networks for 2nd order ODEs with sharp gradients
No full textIn this work, four different methods based on Physics-Informed Neural Networks (PINNs) for solving Differential Equations (DE) are compared: Classic-PINN that makes use of Deep Neural Networks (DNNs) to approximate the DE solution;Deep-TFC improves the efficiency of classic-PINN by employing the constrained expression from the Theory of Functional Connections (TFC) so to analytically satisfy the DE constraints;PIELM that improves the accuracy of classic-PINN by employing a single-layer NN trained via Extreme Learning Machine (ELM) algorithm;X-TFC, which makes use of both constrained expression and ELM. The last has been recently introduced to solve challenging problems affected by discontinuity, learning solutions in cases where the other three methods fail. The four methods are compared by solving the boundary value problem arising from the 1D Steady-State Advection–Diffusion Equation for different values of the diffusion coefficient. The solutions of the DEs exhibit steep gradients as the value of the diffusion coefficient decreases, increasing the challenge of the problem
Physics-Informed Neural Networks and Functional Interpolation for Solving the Matrix Differential Riccati Equation
No full textIn this manuscript, we explore how the solution of the matrix differential Riccati equation (MDRE) can be computed with the Extreme Theory of Functional Connections (X-TFC). X-TFC is a physics-informed neural network that uses functional interpolation to analytically satisfy linear constraints, such as the MDRE’s terminal constraint. We utilize two approaches for solving the MDRE with X-TFC: direct and indirect implementation. The first approach involves solving the MDRE directly with X-TFC, where the matrix equations are vectorized to form a system of first order differential equations and solved with iterative least squares. In the latter approach, the MDRE is first transformed into a matrix differential Lyapunov equation (MDLE) based on the anti-stabilizing solution of the algebraic Riccati equation. The MDLE is easier to solve with X-TFC because it is linear, while the MDRE is nonlinear. Furthermore, the MDLE solution can easily be transformed back into the MDRE solution. Both approaches are validated by solving a fluid catalytic reactor problem and comparing the results with several state-of-the-art methods. Our work demonstrates that the first approach should be performed if a highly accurate solution is desired, while the second approach should be used if a quicker computation time is needed
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