Search results for "Main"
showing 10 items of 4384 documents
Complex powers of elliptic pseudodifferential operators
1986
The aim of this paper is the construction of complex powers of elliptic pseudodifferential operators and the study of the analytic properties of the corresponding kernels kS (x,y). For x=y, the case of principal interest, the domain of holomorphy and the singularities of kS (x,x) are shown to depend on the asymptotic expansion of the symbol. For classical symbols, kS (x,x) is known to be meromorphic on ℂ with simple poles in a set of equidistant points on the real axis. In the more general cases considered here, the singularities may be distributed over a half plane and kS (x,x) can not always be extended to337-2. An example is given where kS (x,x) has a vertical line as natural boundary.
Product of extension domains is still an extension domain
2018
We prove the product of the Sobolev-extension domains is still a Sobolev-extension domain.
Nonlocalization Properties of Time Operators Transformations
2014
It is presented a general approach to the problem of extension of time operators and the associated Lambda transformations on singular measures. It is also shown that Lambda transformations defined on function spaces having the Urysohn property are non localized. Particular attention has been devoted to time and Lambda operators associated with the Walsh-Paley system and to a characterization of their domain and non locality.
Motivic Pattern Extraction in Symbolic Domain
2008
This chapter offers an overview of computational research in motivic pattern extraction. The central questions underlying the topic, concerning the formalization of the motivic structures, the matching strategies and the filtering of the results, have been addressed in various ways. A detailed analysis of these problems leads to the proposal of a new methodology, which will be developed throughout the study. One main conclusion of this review is that the problems cannot be tackled using purely mathematic or geometric heuristics or classical engineering tools, but require also a detailed understanding of the multiple constraints derived by the underlying cognitive context.
L'émergence du référentiel marchand dans la tarification des cliniques privées algériennes : privatisation du financement et changement de paradigme
2021
La convergence tarifaire participe à la privatisation progressive du système de santé algérien amorcée depuis la fin des années 80. Le passage d’une logique de gratuité à une logique marchande pour accéder aux soins représente un bouleversement pour les patients. Afin d’appréhender la formation des tarifs dans le secteur de l’hospitalisation privée, nous avons mixé une enquête qualitative par entretiens semi-directifs auprès de 16 fondateurs de cliniques privées et l’administration d’un questionnaire auprès de 40 médecins permanents de ces cliniques disposant d’une activité à plein temps. Nos résultats montrent que l’absence d’une grille officielle de tarification des prestations de soins a…
Waveguiding properties of a photonic crystal fiber with a solid core surrounded by four large air holes
2009
The polarization-dependent guiding properties of a hexagonal-lattice photonic crystal fiber with a solid-core surrounded by four large air holes are investigated. The appearance of a polarization dependent cutoff frequency, together with several parameters as the birefringence, the modal effective area, the group velocity dispersion and the polarization dependent loss are analyzed. A collection of fibers with different structural parameters were fabricated and characterized. An effective anti-guide structure from at least 450 nm to 1750 nm, a polarizing fiber with a polarization dependent loss of 16 dB/m at 1550 nm, and an endlessly singlemode polarization-maintaining fiber with group biref…
Visible Light Generation and its Influence on Supercontinuum in Chalcogenide As2S3 Microstructured Optical Fiber
2011
We demonstrate visible light generation in chalcogenide As2S3 microstructured optical fiber. The generated visible light causes irreversible damage to the fiber core because of the high absorption coefficient of chalcogenide glasses in the visible band. The SCs (supercontinua) are measured in both untapered and tapered As2S3 fibers, no wider SC is obtained in the tapered one. The SC growth is prevented by the visible light generation since the damage to the fiber core decreases the fiber transmission substantially. This effect can be avoided by designing the fiber to enable the pump source to work in single-mode operation.
A Multicenter Trial of Specific Local Nasal Immunotherapy
2000
Objective: To assess the efficacy and safety of specific local nasal immunotherapy (LNIT) in powder form in patients with allergic rhinitis, using subjective and objective parameters. Study Design: A double-blind randomized multicenter trial of 102 patients with allergic rhinitis who were treated with specific LNIT for 8 consecutive months. Methods: After identifying allergens with the skin prick test and sensitization threshold dose with the specific nasal provocation test, 102 patients were selected, of whom 55 were allergic to mites and 47 were allergic to Graminaceae or Parietaria pollen. The specific treatments were self-administered using an insufflator in two phases (phase 1: increas…
A marching-on in time meshless kernel based solver for full-wave electromagnetic simulation
2012
A meshless particle method based on an unconditionally stable time domain numerical scheme, oriented to electromagnetic transient simulations, is presented. The proposed scheme improves the smoothed particle electromagnetics method, already developed by the authors. The time stepping is approached by using the alternating directions implicit finite difference scheme, in a leapfrog way. The proposed formulation is used in order to efficiently overcome the stability relation constraint of explicit schemes. In fact, due to this constraint, large time steps cannot be used with small space steps and vice-versa. The same stability relation holds when the meshless formulation is applied together w…
Amatas upes hidroloģiskā režīma ilgtermiņa un sezonālās izmaiņas
2017
Darba mērķis ir izvērtēt Amatas upes hidroloģiskā režīma sezonālās un ilgtermiņa izmaiņas mainīga klimata apstākļos. Darbā raksturots Gaujas baseina upju hidroloģiskais režīms un to ietekmējošie faktori, aplūkoti hidroloģiskā režīma pētījumi Latvijā un Baltijā. Veikts Amatas upes baseina fizioģeogrāfiskais raksturojums. Analizēti rezultāti par Amatas upes hidroloģiskā režīma raksturojošo parametru (caurplūdums, temperatūra, ledus izveidošanās un uzlūšanas datumi, ledstāves ilgums) sezonālajām un ilgtermiņa izmaiņām un to savstarpējo korelāciju ar meteoroloģiskajiem parametriem (gaisa temperatūra un atmosfēras nokrišņi) laika periodā no 1921.-2015. gadam. Noteces režīms raksturots, analizējo…