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Numeric Solution of the Fokker-Planck-Kolmogorov Equation

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Engineering（科研） 2013年第12期5卷 975-988页

作者： claudio Floris Department of Civil and Environmental Engineering Politecnico di Milano Milano Italy

The solution of an n-dimensional stochastic differential equation driven by Gaussian white noises is a Markov vector. In this way, the transition joint probability density function (JPDF) of this vector is given by a deterministic parabolic partial differential equation, the so-called Fokker-Planck-Kolmogorov (FPK) equation. There exist few exact solutions of this equation so that the analyst must resort to approximate or numerical procedures. The finite element method (FE) is among the latter, and is reviewed in this paper. Suitable computer codes are written for the two fundamental versions of the FE method, the Bubnov-Galerkin and the Petrov-Galerkin method. In order to reduce the computational effort, which is to reduce the number of nodal points, the following refinements to the method are proposed: 1) exponential (Gaussian) weighting functions different from the shape functions are tested;2) quadratic and cubic splines are used to interpolate the nodal values that are known in a limited number of points. In the applications, the transient state is studied for first order systems only, while for second order systems, the steady-state JPDF is determined, and it is compared with exact solutions or with simulative solutions: a very good agreement is found.

关键词： Stochastic differential Equations Markov Vectors Fokker-Planck-Kolmogorov Equation Finite Element Numeric Solution Modified Hermite Weighting Functions Spline Interpolation

On the Effects of different Interpretations of Stochastic differential Equations

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Applied Mathematics 2019年第11期10卷 876-891页

作者： claudio Floris Department of Civil and Environmental Engineering Politecnico di MilanoMilanoItaly

This paper addresses the problem of the interpretation of the stochastic differential equations (SDE). Even if from a theoretical point of view, there are infinite ways of interpreting them, in practice only Stratonovich’s and Itô’s interpretations and the kinetic form are important. Restricting the attention to the first two, they give rise to two different Fokker-Planck-Kolmogorov equations for the transition probability density function (PDF) of the solution. According to Stratonovich’s interpretation, there is one more term in the drift, which is not present in the physical equation, the so-called spurious drift. This term is not present in Itô’s interpretation so that the transition PDF’s of the two interpretations are different. Several examples are shown in which the two solutions are strongly different. Thus, caution is needed when a physical phenomenon is modelled by a SDE. However, the meaning of the spurious drift remains unclear.

关键词： Stochastic differential Equations White Noise Processes Ito's Interpretation Stratonovich's Interpretation

Current trends in management of hepatitis B virus reactivation in the biologic therapy era

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World Journal of Gastroenterology 2011年第34期17卷 3881-3887页

作者： claudio M Mastroianni Miriam Lichtner Rita Citton Cosmo Del Borgo Angela Rago Helene Martini Giuseppe Cimino Vincenzo Vullo Infectious diseases Unit Fondazione Eleonora Lorillard Spencer Cenci Sapienza University SM Goretti Hospital Hematology Unit Sapienza University SM Goretti Hospital Department of Public Health and Infectious diseases Sapienza University Policlinico Umberto I

Hepatitis B virus (HBV) reactivation represents an emerging cause of liver disease in patients undergoing treatment with biologic agents. In particular, the risk ofHBV reactivation is heightened by the use monoclonalantibodies, such as rituximab (anti-CD20) and alemtuzumab (anti-CD52) that cause profound and longlasting immunosuppression. Emerging data indicatethat HBV reactivation could also develop following theuse of other biologic agents, such as tumor necrosis factor (TNF)-α inhibitors. When HBV reactivation is di-agnosed, it is mandatory to suspend biologic treatmentand start antiviral agents immediately. However, preemptive antiviral therapy prior to monoclonal antibodyadministration is crucial in preventing HBV reactivationand its clinical consequences. Several lines of evidencehave shown that risk of HBV reactivation is greatlyreduced by the identifi cation of high-risk patients andthe use of prophylactic antiviral therapy. In this article, we discuss current trends in the management of HBV reactivation in immunosuppressed patients receiving biologic therapy, such as rituximab, alemtuzumab and TNF-α antagonists.

关键词： Hepatitis B virus Virus reactivation Rituximab Tumor necrosis factor-α antagonists Biologic agents Antiviral drugs

Robot impedance control and passivity analysis with inner torque and velocity feedback loops

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Control Theory and Technology 2016年第2期14卷 97-112页

作者： Michele FOCCHI Gustavo A. MEDRANO-CERDA Thiago BOAVENTURA Marco FRIGERIO claudio SEMINI Jonas BUCHLI Darwin G. CALDWELL Department of Advanced Robotics Istituto Italiano di Tecnologia (liT) via Morego 30 16163 Genova Italy Agile & Dexterous Robotics Lab ETH Zurich Tannenstrasse 3 8092 Zurich Switzerland Received 21 January 2015 revised 10 December 2015 accepted 10 December 2015

Impedance control is a well-established technique to control interaction forces in robotics. However, real implementations of impedance control with an inner loop may suffer from several limitations. In particular, the viable range of stable stiffness and damping values can be strongly affected by the bandwidth of the inner control loops （e.g., a torque loop） as well as by the filtering and sampling frequency. This paper provides an extensive analysis on how these aspects influence the stability region of impedance parameters as well as the passivity of the system. This will be supported by both simulations and experimental data. Moreover, a methodology for designing joint impedance controllers based on an inner torque loop and a positive velocity feedback loop will be presented. The goal of the velocity feedback is to increase （given the constraints to preserve stability） the bandwidth of the torque loop without the need of a complex controller.

关键词： Impedance control torque control passivity and stability analysis

Predicted and measured soil retention curve parameters in Lombardy region north of Italy

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International Soil and Water Conservation Research 2016年第3期4卷 207-214页

作者： Fatma Wassar claudio Gandolfi Michele Rienzner Enrico Antonio Chiaradia Ettore Bernardoni IBIMET-CNR via Madonna del Piano 1050019 Sesto F.noFIItaly dipartimento di Scienze Agrarie e Ambientali(diSAA) Universitàdegli Studi di Milano(UNIMI)Via Celoria 220133 MilanoItaly ISSTEG Institut Supérieur des Sciences et Techniques des EauxcitéAmal 46072 GabèsTunisia

Water retention characteristics are fundamental input parameters in any modeling study on water flow and solute *** properties are difficult to measure and for that reason,we usually need to use direct and indirect methods to determine *** extensive comparison between measured and estimated results is needed to determine their applicability for a range of different *** this study attempts to make a contribution specifically in this *** properties were determined in two representative sites located in Landriano field,in Lombardy region,northern *** the laboratory we used the pressure plate apparatus and the tensiometric *** soil water retention was determined including measurements of soil water content with SENTEK probes and matric potential with *** soil waer retention curves(SWRC)were also settled on with some recently developed pedo-transfert functions(PTFs).Field retention curves were compared against those obtained from PTFs estimations and laboratory *** comparison showed that laboratory measurements were the most *** had the highest ranking for the validation indices(RMSE ranging between 2.4%and 7.7%and bias between 0.1%and 6.4%).The second best technique was the PTF Rosetta(Schaap et al.2001).They perform only slightly poorer than the laboratory measurements(RMSE ranging between 2.7%and 10%and bias between 0.3%and 7.7%).The lowest prediction accuracy is observed for the Rawls and Brakensiek(1985)PTF(RMSE ranging between 6.3%and 17%and bias between 5%and 10%)which is in contradiction with previous finding(Calzolari et al.,2001),showing that this function is well representing the retention characteristics of the *** to time and cost investments of laboratory and field measurements,we conclude that the Rosetta PTF developed by Schaap et al.(2001)appears to be the best to predict the soil moisture retention curve from easily available soil properties in the Lombardy area a

关键词： Comparison Laboratory water retention Field measurements Curve measurements Pedo-transfert functions

Modelling SARS-CoV-2 unreported cases in Italy: Analysis of serological survey and vaccination scenarios

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Infectious disease Modelling 2021年第1期6卷 909-923页

作者： Marco claudio Traini Carla Caponi Riccardo Ferrari Giuseppe Vittorio De Socio dipartimento di Fisica Universita Degli Studi di TrentoVia Sommarive 14I-38123Trento-PovoItaly Clinica Geriatrica Azienda Ospedaliero-UniversitariaPiazzale Gambuli 106132PerugiaItaly Bilubah LLC 30 N.Gould StSuite 6739SheridanWY82801USA Clinica Malattie Infettive Azienda Ospedaliero-UniversitariaPiazzale Gambuli 106132PerugiaItaly

Objectives:Aim of the present paper is the study of the large unreported component,characterizing the SARS-CoV-2 epidemic event in Italy,taking advantage of the Istat *** attention is devoted to the sensitivity and specificity of the serological test and their ***:The model satisfactory reproduces the data of the Italian survey showing a relevant predictive power and relegating in a secondary position models which do not include,in the simulation,the presence of asymptomatic *** corrections due to the serological test sensitivity(in particular those ones depending on the symptoms onset)are crucial for a realistic analysis of the unreported(and asymptomatic)***:The relevant presence of an unreported component during the second pandemic wave in Italy is confirmed and the ratio of reported to unreported cases is predicted to be roughly 1:4 in the last months of year 2020.A method to correct the serological data on the basis of the antibody sensitivity is suggested and systematically *** asymptomatic component is also studied in some detail and its amount quantified.A model analyses of the vaccination scenarios is performed confirming the relevance of a massive campaign(at least 80000 immunized per day)during the first six months of the year 2021,to obtain important immunization effects within August/September 2021.

关键词： ARS-CoV-2 Asymptomatic and unreported cases Seroprevalence Epidemiological models Sensitivity and specificity of the serological tests Vaccination

Lesion presenting with a “blue amber” pattern

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World Journal of Clinical Cases 2016年第10期4卷 333-335页

作者： Calogero Pagliarello Francesca Peccerillo Alfredo Zucchi Rocco Giuseppe Tortorella Roberto Ricci Ignazio Stanganelli claudio Feliciani Sergio di Nuzzo Section of Dermatology Department of Clinical and Experimental MedicineUniversity of Parma Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori(IRST)IRCCS

Atypical fibroxanthoma(AFX) is a spindle cell neoplasm with low metastatic potential but high tendency to recur after surgery. Because of the rarity of this lesion and its aspecific clinical features, AFX could be easily misdiagnosed and undertreated by many clinicians who encounter them. Dermoscopy represents a valuable tool for easily assessing skin lesions, even though histological examination is required for final diagnosis. We report a case of a cheek lesion with dermoscopic "blue amber pattern", easily recognisable and not observed in others skin tumours, which could represent an additional feature useful in differentiating this tumour from other skin neoplasms.

关键词： Atypical fibroxanthoma Dermoscopy Blue amber pattern Vascular structures

Raman spectra and vibrational analysis of CsPbI3:A fast and reliable technique to identify lead halide perovskite polymorphs

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Journal of Materiomics 2021年第1期7卷 127-135页

作者： Jessica Satta claudio Melis Carlo Maria Carbonaro Andrea Pinna Manuel Salado Daniel Salazar Pier Carlo Ricci Department of Physics University of CagliariS.p.No.8 Km 0.70009042MonserratoCAItaly Department of Mechanical Chemical and Materials EngineeringCINSAINSTMUniversity of CagliariVia Marengo 2CagliariI-09123Italy BCMaterials Basque Center for MaterialsApplications and NanostructuresUPV/EHU Science Park48940LeioaSpain

A major issue in the development of Lead halide perovskites is the assessment of the crystal structure of the samples,due to their typically limited time-stability,and the understanding of the role of external factors that can induce a crystal phase transformation(such as humidity,intense light flux,temperature,etc.).In this perspective,it is of utmost importance to have at disposal a fast and reliable experimental tool able to give an immediate indication of the polymorph of the sample with the possibility to integrate in-situ measurements for constant *** this paper we propose Raman spectroscopy as the ideal technique to solve this *** vibrational analysis of CsPbI3 in the a-phase and 5-phase and of the Cs4PbI6 secondary phase is reported and all the vibrational modes are assigned by comparing experimental spectra of the phases to Raman modes calculated within the DFT ***,the mechanism of laser induced phase degradation was studied using in-situ Raman measurements providing new insights on the secondary phase generated during the process.

关键词： Raman spectroscopy CsPb13 Inorganic lead halide perovskites Phase transformation

SEGNALAZIONE di PARTICOLARI FORME PERIGLACIALI PRESSO LA FRONTE DEL GHIACCIAIO di FELLARIA(Val Malenco,Valtellina)

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Natural disaster Reduction in China 1986年第1期 347-350页

作者： claudio SMIRAGLIA

Finding of unusual periglacial landforms near the snout of the Fellaria glacier(Val ***).In the surface exposed beyond the margins of the present West Fellaria Glacier(Val Malenco,Valtelli-na).characterized by fluted ground moraines,unusual periglacial landforms have been *** are pat-terned grounds with fine materials in the central part and often uplifted pebbles in the edge;a large boulder(main height,50 cm)is always placed at the head of the forms *** these landforms result bythe superimposition of glacial processes(boulder deposit and flutes formation)and periglacial processes(reorganization of the clastic materials of the flutes).

关键词： Si area di Val Malenco,Valtellina SEGNALAZIONE di PARTICOLARI FORME PERIGLACIALI PRESSO LA FRONTE DEL GHIACCIAIO di FELLARIA TR