Search results for " generation."
showing 10 items of 1108 documents
In-Depth Analysis of Pricing Problem Relaxations for the Capacitated Arc-Routing Problem
2015
Recently, Bode and Irnich [Bode C, Irnich S (2012) Cut-first branch-and-price-second for the capacitated arc-routing problem. Oper. Res. 60(5):1167–1182] presented a cut-first branch-and-price-second algorithm for solving the capacitated arc-routing problem (CARP). The fundamental difference to other approaches for exactly solving the CARP is that the entire algorithm works directly on the typically sparse underlying graph representing the street network. This enables the use of highly efficient dynamic programming-based pricing algorithms to solve the column-generation subproblem also known as the pricing problem. The contribution of this paper is the in-depth analysis of the CARP pricing…
Effective Handling of Dynamic Time Windows and Its Application to Solving the Dial-a-Ride Problem
2015
A dynamic time window relates to two operations that must be executed within a given time meaning that the difference between the points in time when the two operations are performed is bounded from above. The most prevalent context of dynamic time windows is when precedence is given for the two operations so that it is a priori specified that one operation must take place before the other. A prominent vehicle routing problem with dynamic time windows and precedence is the dial-a-ride problem (DARP), where user-specified transportation requests from origin to destination points must be serviced. The paper presents a new branch-and-cut-and-price solution approach for the DARP, the prototypi…
Gluon mass generation in the presence of dynamical quarks
2013
We study in detail the impact of dynamical quarks on the gluon mass generation mechanism, in the Landau gauge, for the case of a small number of quark families. As in earlier considerations, we assume that the main bulk of the unquenching corrections to the gluon propagator originates from the fully dressed quark-loop diagram. The nonperturbative evaluation of this diagram provides the key relation that expresses the unquenched gluon propagator as a deviation from its quenched counterpart. This relation is subsequently coupled to the integral equation that controls the momentum evolution of the effective gluon mass, which contains a single adjustable parameter; this constitutes a major impr…
Monte Carlo simulation of high‐order harmonics generation in bulk semiconductors and submicron structures
2004
To qualify the feasibility of standard semiconductor materials and Schottky‐barrier diodes (SBDs) for THz high‐order harmonic generation and extraction, the harmonic intensity, intrinsic noise and signal‐to‐noise ratio are calculated by the Monte Carlo method when a periodic high‐frequency large‐amplitude external signal is applied to a semiconductor device. Due to very high signal‐to‐noise ratio heavily doped GaAs SBDs are found to exhibit conditions for frequency mixing and harmonic extraction that are definitively superior to those of bulk materials. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Design and performances of a high temperature superconducting axial flux generator
2013
An important quality index of electric machine is the power density: it is known that axial flux machine tends to have a higher power density than the radial machines. As a result they are becoming more and more used in applications where the power density is a critical issues. However, the best way to enhance the power density is to increase the value of the airgap field and this could be achieved by using a superconducting excitation. Many projects have been developed in the world in order to develop both superconducting generator and superconducting motor, but in most of these programs the geometry of the machine has been based on radial machines [1]. All of these approaches show the fea…
Mechanism of the Citrate Transporters in Carbohydrate and Citrate Cometabolism in Lactococcus and Leuconostoc Species
1998
ABSTRACT Citrate metabolism in the lactic acid bacterium Leuconostoc mesenteroides generates an electrochemical proton gradient across the membrane by a secondary mechanism (C. Marty-Teysset, C. Posthuma, J. S. Lolkema, P. Schmitt, C. Divies, and W. N. Konings, J. Bacteriol. 178:2178–2185, 1996). Reports on the energetics of citrate metabolism in the related organism Lactococcus lactis are contradictory, and this study was performed to clarify this issue. Cloning of the membrane potential-generating citrate transporter (CitP) of Leuconostoc mesenteroides revealed an amino acid sequence that is almost identical to the known sequence of the CitP of Lactococcus lactis . The cloned gene was exp…
Unequal Attainments: Ethnic educational inequalities in ten Western countries
2014
Western countries have become increasingly diverse in recent decades and these demographic trends are certain to continue. The resulting ethnic diversity is a major challenge to policy-makers, who need to tackle issues of social justice and social integration. Education plays a pivotal role since it is the major stepping stone for the children of immigrants to successful economic integration and also plays a major role in social and political integration more generally since education gives access to the skills, resources and contacts which enable individuals to participate fully in the life of their society. Our central research questions are: Do the descendants of migrants experience equa…
LIFE CARE ANNUITIES (LCA) EMBEDDED IN A NOTIONAL DEFINED CONTRIBUTION (NDC) FRAMEWORK
2016
AbstractThis paper examines the possibility of embedding public long-term care (LTC) insurance within the retirement pension system, i.e. introducing life care annuities into a notional defined contribution framework. To do this, we develop a multistate overlapping generations model that includes the so-called survivor dividend and give special attention to the assumptions made about mortality rates for dependent persons and LTC incidence rates, which largely determine the contribution rate assigned to LTC. The proposed model could be of interest to policymakers because it could be implemented without too much difficulty, it would universalize LTC coverage with a “fixed” cost, and it would …
Integrating retirement and permanent disability in NDC pension schemes
2015
ABSTRACTIn this article, we develop a theoretical basis for integrating retirement and permanent disability using a generic nonfinancial defined contribution framework. The methodology we use relies on a multistate overlapping generations model that includes the so-called survivor dividend. Currently, this feature can only be found in the Swedish defined contribution (DC) scheme. The results achieved in the numerical example we present endorse the fact that the model works well. Special attention is given to the assumptions made about mortality rates for disabled people and disability incidence rates, which largely determine the contribution rate assigned to disability. The model could be o…
La relazione educativa “affettiva”: ripensare il rapporto tra scuola e famiglia
2018
Educational co-planning and co-responsibility between school and family have been a subject of pedagogical consideration for several years. The literature identifies critical points in the construction of educational partnerships between them because of transformations occurred both in family and in school: they seem to have missed their clear symbolic value. Once, the roles of the adults (teacher or parent) were more important than the persons who actually embodied them; now, instead, we observe a loss in the symbolic value of generational gap and this has implied a change in the educational relationship. It is a shift from an educational style mainly based on authority and norms to one ba…