Search results for "Variable"
showing 10 items of 1674 documents
Inventory policies and information sharing in multi-echelon supply chains
2011
The aim of this article is to show how to modify a replenishment rule in relation to the operational information shared by suppliers. More specifically, we present a model of an Automatic Pipeline Variable Inventory and Order-Based Production Control System rule for a multi-echelon supply chain characterised by different increasing levels of shared information. A numerical study is presented to underline the performance differences for three variants of the smoothing order rule in terms of bullwhip reduction, inventory stability and operational and customer responsiveness. Results show how the effectiveness of a smoothing replenishment rule depends on the level of information sharing.
Control zeros and nonminimum phase LTI mimo systems
1999
Abstract The paper presents a new, general, inverse-model/output-zeroing approach to zeros of LTI discrete-time multivariable, possibly nonsquare systems. It is shown on simple examples that the existing definitions of multivariable zeros fail to detect certain important zeros which contribute to zeroing the system output. As a result, a concept of ‘control zeros’ is introduced, followed by a general redefinition of minimum/nonminimum phase systems, both new contributions being based on the notion of (generalized) inverse systems. Output-zeroing/inverse-model/minimum-variance control-related justifications of the new approach are presented.
Lagrangian dynamics and possible isochronous behavior in several classes of non-linear second order oscillators via the use of Jacobi last multiplier
2015
Abstract In this paper, we employ the technique of Jacobi Last Multiplier (JLM) to derive Lagrangians for several important and topical classes of non-linear second-order oscillators, including systems with variable and parametric dissipation, a generalized anharmonic oscillator, and a generalized Lane–Emden equation. For several of these systems, it is very difficult to obtain the Lagrangians directly, i.e., by solving the inverse problem of matching the Euler–Lagrange equations to the actual oscillator equation. In order to facilitate the derivation of exact solutions, and also investigate possible isochronous behavior in the analyzed systems, we next invoke some recent theoretical result…
Spatial mismatch through local public employment agencies Answers from a French quasi-experiment Spatial Mismatch through Local Public Employment Age…
2015
Using the unanticipated creation of a new agency in the French region of Lyon as a quasi-natural experiment, we question whether distance to local public employment agencies (LPEAs) is a new channel for spatial mismatch. Contrary to past evidence based on aggregated data and consistently with the spatial mismatch literature, we find no evidence of a worker/agency spatial mismatch, which pleads for a resizing of the French LPEA network. However, echoing with the literature on the institutional determinants of the local public employment agencies' efficiency, we do find detrimental institutional transitory effects.
Interactions, spillovers de connaissance et croissance des villes européennes. Faut-il préférer la géographie, le climat institutionnel ou les réseau…
2013
Knowledge spillovers within urban economies are also sources of spillovers between cities. We examine how knowledge spillovers influenced the economic growth of 82 European metropolises over the 1990-2005 period. We model knowledge spillovers between cities on the basis of five specific interaction patterns based on geography, networks of multinational firms in advanced services, institutional climate and two combinations of these factors. Spatial models are estimated to detail the effects of growth factors in terms of spillovers and externalities. We show that spillovers are local rather than global and that interactions among cities accelerate the convergence process based on gross value …
Higher Education Institutions Quality and Graduate Wages in Tunisia
2017
International audience; We estimate the effect of university characteristics on the return to higher education in Tunisia. We use a variety of administrative data from the Ministry of Higher Education and Research, the Ministry of Vocational Training and Employment and the National Social Security Fund. We consider econometric approaches based on multilevel modeling, which distinguishes more precisely between the effects of individual factors and institutional factors on earnings. Our findings confirm the relationship between the income and some university characteristics such as the number of permanent teachers, the selectivity of the higher learning institutions at the academic orientatio…
L'estimation de modèles à variable dépendante dichotomique
1977
Document de travail de l'IME, n°20, avril 1977en ligne sur http://lara.inist.fr/bitstream/handle/2332/2144/IME_DT_77_20.pdf?sequence=1; e texte a pour objet l'étude de l'estimation de la probabilité de réalisation d'un évènement E, étant donné un certain nombre de caractéristiques associées à cette éventualité. Deux modèles sont envisagés, à savoir le modèle de régression linéaire et le modèle de régression logistique. Le premier, qui revient à estimer une fonction de probabilité linéaire ne vérifie plus les hypothèses classiques des moindres carrés ordinaires. Une première amélioration consiste alors à estimer le modèle par la méthode des moindres carrés généralisés. Cependant, outre le pr…
Productivity analysis of Latvian companies using ORBIS database
2021
International audience; This research study uses ORBIS microdata at the company level to analyse productivity of 167 thousand economically active Latvian companies over 2011-2018. The aim of the study is twofold-to find factors consistently associated with productivity at the company level; and to recommend possible criteria for companies to receive a state support (from the view of enhancing aggregate productivity in the long term). Our research results show that productivity of Latvian companies is positively related to their size, age, as well as location closer to Riga and other big cities. However, there is a substantial within-group variation in productivity between companies. Multiva…
NEIGHBORHOOD EFFECTS IN SPATIAL HOUSING VALUE MODELS. THE CASE OF THE METROPOLITAN AREA OF PARIS (1999)
2009
In hedonic housing models, the spatial dimension of housing values are traditionally processed by the impact of neighborhood variables and accessibility variables. In this paper we show that spatial effects might remain once neighborhood effects and accessibility have been controlled for. We notably stress on three sides of neighborhood effects: social capital, social status and social externalities and consider the accessibility to the primary economic center as describing the urban spatial trend. Using spatial econometrics specifications of the hedonic equation, we estimate whether spatial effects impact the housing values. Our empirical case concerns the Metropolitan Area (MA) of Paris i…
Learning with the kernel signal to noise ratio
2012
This paper presents the application of the kernel signal to noise ratio (KSNR) in the context of feature extraction to general machine learning and signal processing domains. The proposed approach maximizes the signal variance while minimizes the estimated noise variance in a reproducing kernel Hilbert space (RKHS). The KSNR can be used in any kernel method to deal with correlated (possibly non-Gaussian) noise. We illustrate the method in nonlinear regression examples, dependence estimation and causal inference, nonlinear channel equalization, and nonlinear feature extraction from high-dimensional satellite images. Results show that the proposed KSNR yields more fitted solutions and extract…