Search results for "fixed"

Eigenvectors of k–ψ-contractive wedge operators

AbstractWe present new boundary conditions under which the fixed point index of a strict-ψ-contractive wedge operator is zero. Then we investigate eigenvalues and corresponding eigenvectors of k–ψ-contractive wedge operators.

Approximation algorithm for constrained coupled-tasks scheduling problem

2014

International audience; We tackle the makespan minimization coupled-tasks problem in presence of compatibility constraints. In particular, we focus on stretched coupled-tasks, i.e. coupled-tasks having the same sub-tasks execution time and idle time duration. In such context, we propose some complexity results according to several parameters and we design an efficient polynomial-time approximation algorithm.

Time and work generalised precedence relationships in project scheduling with pre-emption: An application to the management of Service Centres

2012

Abstract In this paper we present an application of project scheduling concepts and solution procedures for the solution of a complex problem that comes up in the daily management of many company Service Centres. The real problem has been modelled as a multi-mode resource-constrained project scheduling problem with pre-emption, time and work generalised precedence relationships with minimal and maximal time lags between the tasks and due dates. We present a complete study of work GPRs which includes proper definitions, a new notation and all possible conversions amongst them. Computational results that show the efficiency of the proposed hybrid genetic algorithm and the advantages of allowi…

Nonlinear multivalued Duffing systems

2018

We consider a multivalued nonlinear Duffing system driven by a nonlinear nonhomogeneous differential operator. We prove existence theorems for both the convex and nonconvex problems (according to whether the multivalued perturbation is convex valued or not). Also, we show that the solutions of the nonconvex problem are dense in those of the convex (relaxation theorem). Our work extends the recent one by Kalita-Kowalski (JMAA, https://doi.org/10.1016/j.jmaa. 2018.01.067).

Is massless quantum electrodynamics a free-field theory?

1976

It is shown that if the photon wave-function renormalization constant is finite, then in the limit of zero fermion mass, quantum electrodynamics is a free- field theory.

Responsiveness to change and reliability of measurement of radiographic joint space width in osteoarthritis of the knee: a systematic review

2011

Import JabRef | WosArea Orthopedics; Rheumatology; International audience; Objective: The goal of this systematic review was to report the responsiveness to change and reliability of conventional radiographic joint space width (JSW) measurement. Method: We searched the PubMed and Embase databases using the following search criteria: [osteoarthritis (OA) (MeSH)] AND (knee) AND (X-ray OR radiography OR diagnostic imaging OR radiology OR disease progression) AND (joint space OR JSW or disease progression). We assessed responsiveness by calculating the standardized response mean (SRM). We assessed reliability using intra- and inter-reader intra-class correlation (ICC) and coefficient of variati…

The Sehgal’s Fixed Point Result in the Framework of ρ-Space

2022

In this paper, we prove a fixed point theorem of Sehgal type (see Sehgal, V.M., Proc Amer Math Soc 23: 631–634, 1969) in a more general setting of ρ-space (see Secelean, N.A. and Wardowski, D., Results Math, 72: 919–935, 2017). In this way, we can find, as particular cases, some results of Sehgal type in metric, b-metric and rectangular b-metric spaces.

Photocatalytic oxidation of 4-methoxybenzyl alcohol to p-anisaldehyde in a fixed bed continuous reactor,

2008

An Innovative Pricing Method for Telecommunication Services Pricing through American Options

2009

With the evolution of telecommunication networks and of their services the role of service provider is changed, so nowadays there is a coexistence of Network Operators and Virtual Operators. The difference between these players is not in the way they offer a service but primarily in their economic objectives and risk attitudes. Essentially, Network Operators own their infrastructures and typically have to sustain both fixed costs (CAPEX) and recurrent costs (OPEX), while Virtual Operators may have a simpler cost structure, mainly consisting of OPEX for the hire of network resources. Since these two operators can provide the same service in two different markets, their objectives differ subs…

American Options Based Service Pricing For Virtual Operators

2008

In the recent years, the role of service provider has split into two broad categories: Network Operators, offering services over their networks, and Virtual Operators, providing services over leased resources. What differentiates these players is to a minor extent a matter of enhanced service offer, and primarily a matter of economic objectives and risk attitudes. Essentially, Network Operators own their infrastructures and typically have to sustain both fixed costs (CAPEX) and recurrent costs (OPEX), while Virtual Operators may have a simpler cost structure, mainly consisting of OPEX for hiring the network. Correspondingly, the objectives of these players may differ profoundly: on one hand…