177 research outputs found
A theory of the infinite horizon LQ-problem for composite systems of PDEs with boundary control
We study the infinite horizon Linear-Quadratic problem and the associated
algebraic Riccati equations for systems with unbounded control actions. The
operator-theoretic context is motivated by composite systems of Partial
Differential Equations (PDE) with boundary or point control. Specific focus is
placed on systems of coupled hyperbolic/parabolic PDE with an overall
`predominant' hyperbolic character, such as, e.g., some models for
thermoelastic or fluid-structure interactions. While unbounded control actions
lead to Riccati equations with unbounded (operator) coefficients, unlike the
parabolic case solvability of these equations becomes a major issue, owing to
the lack of sufficient regularity of the solutions to the composite dynamics.
In the present case, even the more general theory appealing to estimates of the
singularity displayed by the kernel which occurs in the integral representation
of the solution to the control system fails. A novel framework which embodies
possible hyperbolic components of the dynamics has been introduced by the
authors in 2005, and a full theory of the LQ-problem on a finite time horizon
has been developed. The present paper provides the infinite time horizon
theory, culminating in well-posedness of the corresponding (algebraic) Riccati
equations. New technical challenges are encountered and new tools are needed,
especially in order to pinpoint the differentiability of the optimal solution.
The theory is illustrated by means of a boundary control problem arising in
thermoelasticity.Comment: 50 pages, submitte
On globally defined semianalytic sets
In this work we present the concept of -semianalytic subset of a real
analytic manifold and more generally of a real analytic space. -semianalytic
sets can be understood as the natural generalization to the semianalytic
setting of global analytic sets introduced by Cartan (-analytic sets for
short). More precisely is a -semianalytic subset of a real analytic
space if each point of has a neighborhood such
that is a finite boolean combinations of global analytic equalities
and strict inequalities on . By means of paracompactness -semianalytic
sets are the locally finite unions of finite boolean combinations of global
analytic equalities and strict inequalities on .
The family of -semianalytic sets is closed under the same operations as
the family of semianalytic sets: locally finite unions and intersections,
complement, closure, interior, connected components, inverse images under
analytic maps, sets of points of dimension , etc. although they are defined
involving only global analytic functions. In addition, we characterize
subanalytic sets as the images under proper analytic maps of -semianalytic
sets.
We prove also that the image of a -semianalytic set under a proper
holomorphic map between Stein spaces is again a -semianalytic set. The
previous result allows us to understand better the structure of the set
of points of non-coherence of a -analytic subset of a real analytic
manifold . We provide a global geometric-topological description of
inspired by the corresponding local one for analytic sets due to
Tancredi-Tognoli (1980), which requires complex analytic normalization. As a
consequence it holds that is a -semianalytic set of dimension
.Comment: 32 pages, 3 figure
The Walking Test: Use in clinical practice
Exercise Capacity is the expression of the cardiovascular and of metabolic organic efficiency and represents a important prognostic marker. The Six Minute Walking Test is adopted in the practice for exercise capacity evaluation in the normal subject as in pneumologic or cardiac rehabilitation programs, and in both pediatric and elderly ages. The aim of the work is to present a practical summary of the application of the six minutes walking test, according to the American Thoracic Society statement. We reviewed the various experiences of its application, and reported the indications, clinical interpretation parameters, relationship and correlation between functional and clinical parameters (hospitalization, quality of life, therapy and exercise control response and compliance), the basic and advanced protocol, the application modality, the reporting models, and the educational checklist
2019 Italian Society of Cardiology census on telemedicine in cardiovascular disease : a report from the working group on telecardiology and informatics
Background The aim of this study was to assess by a census supported by the Italian Society of Cardiology (Societ\ue0 Italiana di Cardiologia, SIC) the present implementation of telemedicine in the field of cardiovascular disease in Italy.
Methods A dedicated questionnaire was sent by email to all the members of the SIC: data on telemedicine providers, service provided, reimbursement, funding and organisational solutions were collected and analysed.
Results Reported telemedicine activities were mostly stable and public hospital based, focused on acute cardiovascular disease and prehospital triage of suspected acute myocardial infarction (prehospital ECG, always interpreted by a cardiologist and not automatically reported by computerised algorithms). Private companies delivering telemedicine services in cardiology (ECGs, ambulatory ECG monitoring) were also present. In 16% of cases, ECGs were also delivered through pharmacies or general practitioners. ICD/CRT-D remote control was performed in 42% of cases, heart failure patient remote monitoring in 37% (21% vital parameters monitoring, 32% nurse telephone monitoring). Telemedicine service was public in 74% of cases, paid by the patient in 26%. About half of telemedicine service received no funding, 17% received State and/or European Union funding.
Conclusions Several telemedicine activities have been reported for the management of acute and chronic cardiovascular disease in Italy. The whole continuum of cardiovascular disease is covered by telemedicine solutions. A periodic census may be useful to assess the implementation of guidelines recommendations on telemedicine
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