Search results for "Circle"

On compactness of the difference of composition operators

2004

Abstract Let φ and ψ be analytic self-maps of the unit disc, and denote by C φ and C ψ the induced composition operators. The compactness and weak compactness of the difference T = C φ − C ψ are studied on H p spaces of the unit disc and L p spaces of the unit circle. It is shown that the compactness of T on H p is independent of p ∈[1,∞). The compactness of T on L 1 and M (the space of complex measures) is characterized, and examples of φ and ψ are constructed such that T is compact on H 1 but non-compact on L 1 . Other given results deal with L ∞ , weakly compact counterparts of the previous results, and a conjecture of J.E. Shapiro.

Robust Finite-Time Control of Switched Linear Systems and Application to a Class of Servomechanism Systems

2015

This paper investigates finite-time (FT) stability and stabilization problems for a class of switched linear systems with polytopic uncertainties. Both stable and unstable subsystems are considered to coexist in the system, and a new concept of extended FT stability is proposed as the first attempt. A stability criterion is first established, where the admissible maximum switching number is obtained while ensuring extended FT stability of switched linear systems with time-varying delays under a given maximum ratio between the running time of unstable subsystems and the running time of stable subsystems. Sufficient conditions on the existence of desired memory state-feedback controllers are …

Operationalization of un-captured GDP - Innovation stream under new global mega-trends

2016

With the understanding that current ICT-driven global development depends on a trend shifting from traditional co-evolution of computer-initiated ICT, captured GDP, and economic functionality to new co-evolution of the Internet, un-captured GDP, and supra-functionality beyond economic value, the following hypothetical view was postulated: The disparity between the world's ICT leader countries with respect to happiness/welfare amidst great stagnation (Finland) or conspicuous economic growth (Singapore) can be attributed to the difference of the state in the above shifting trends. The foregoing hypothetical view was demonstrated on the basis of an empirical analysis measuring dependency on un…

Sobolev homeomorphic extensions onto John domains

2020

Abstract Given the planar unit disk as the source and a Jordan domain as the target, we study the problem of extending a given boundary homeomorphism as a Sobolev homeomorphism. For general targets, this Sobolev variant of the classical Jordan-Schoenflies theorem may admit no solution - it is possible to have a boundary homeomorphism which admits a continuous W 1 , 2 -extension but not even a homeomorphic W 1 , 1 -extension. We prove that if the target is assumed to be a John disk, then any boundary homeomorphism from the unit circle admits a Sobolev homeomorphic extension for all exponents p 2 . John disks, being one sided quasidisks, are of fundamental importance in Geometric Function The…

2020

Background: Computed tomography angiography (CTA) is frequently used with computed tomography perfusion imaging (CTP) to evaluate whether endovascular vasospasm treatment is indicated for subarachnoid hemorrhage patients with delayed cerebral ischemia. However, objective parameters for CTA evaluation are lacking. In this study, we used an automated, investigator-independent, digital method to detect vasospasm, and we evaluated whether the method could predict the need for subsequent endovascular vasospasm treatment. Methods: We retrospectively reviewed the charts and analyzed imaging data for 40 consecutive patients with subarachnoid hemorrhages. The cerebrovascular trees were digitally rec…

Global extrapolation with a parallel splitting method

1992

Extrapolation with a parallel splitting method is discussed. The parallel splitting method reduces a multidimensional problem into independent one-dimensional problems and can improve the convergence order of space variables to an order as high as the regularity of the solution permits. Therefore, in order to match the convergence order of the space variables, a high order method should also be used for the time integration. Second and third order extrapolation methods are used to improve the time convergence and it was found that the higher order extrapolation method can produce a more accurate solution than the lower order extrapolation method, but the convergence order of high order extr…

The use of literature in the EFL classroom : students' perception

2018

Kirjallisuutta ja lukupiirejä on käytetty englannin kielen opetuksessa jo vuosikymmenten ajan. Tämä ei ole yllättävää, sillä niillä on monia kielen opiskelijoille hyödyllisiä ominaisuuksia. Kirjallisuus tarjoaa opiskelijoille autenttista materiaalia opiskellulla kohdekielellä ja kehittää samalla heidän kielitaitoaan ja kulttuurista tietämystään. Lukupiirit kannustavat opiskelijoita keskustelemaan kirjallisuudesta ja jakamaan henkilökohtaisia kokemuksiaan turvallisessa ympäristössä, mikä motivoi heitä lukemaan ja puhumaan vieraalla kielellä. Tämän tutkimuksen tarkoituksena oli tarkastella opiskelijoiden kokemuksia ja näkemyksiä kirjallisuuden sekä lukupiirien käytöstä englannin kielen opiske…

DEVELOPMENT OF S/MAR MINICIRLES VECTOR FOR PERSISTENT EXPRESSION IN VIVO.

2009

An ideal vector for gene therapy must fulfil the following requirements: non-toxicity, mitotic stability and persistent therapeutic levels of transgene expression. Viral vectors are widely used due to their ability to sustain prolonged expression. Their potentially tumorigenic effects are a limiting factor for in vivo applications. Non-viral vectors, which can be designed to be free from viral sequences, are a promising alternative for gene transfer although they often produce transient transgene expression. This limitation of this vector type is primarily due to bacterial sequences they contain and these have proven to be toxic for the mammalian cells as they contain a high number of unmet…

General Practitioners-CommunityPharmacists practice groups: Analysis of the potentialities and limits of this practice through its implementation in …

2023

Practice groups involving general practitioners and community pharmacists have been developed in several European countries (Belgium, the Netherlands, Switzerland) since the 1980s. Each country has implemented this practice using a different model with similarities but also specificities. Each model has encountered different dynamics during its implementation thanks to a significant and even growing participation of professionals in the Netherlands and Switzerland and, to a lesser extent, in Belgium. According to the research that has studied the implementation of these models, the potential of this practice is important in terms of improving the quality of drug prescription and in its cost…

A critical assessment of methods for the determination of the shear stress amplitude in multiaxial fatigue criteria belonging to critical plane class

2015

Abstract Multiaxial high cycle fatigue criteria based on the critical plane approach necessitate unambiguous definitions of the amplitude and mean value of the shear stress (τa and τm) acting on the material planes. Four of the existing definitions relate the values of τa and τm to a geometrical element of the curve described by the tip of the shear stress vector (curve Ψ), respectively, the radius of the Minimum Circumscribed Circle, the Longest Chord, the Longest Projection, the diagonal of the Maximum Rectangular Hull (MRH). In this paper a critical assessment of the above definitions is proposed, focusing on that based on the concept of MRH, which is the most recently developed. The mai…