Search results for "Crete"
showing 10 items of 2495 documents
Age and productivity as determinants of firm survival over the industry life cycle
2017
AbstractThis paper contributes to fill the gap between the literature on the determinants of firm survival and the empirical works on the industry life cycle (ILC). Using a representative sample of Spanish firms with 10 or more employees over the period 1993–2009, the role played by firm age and productivity in firm survival is empirically analysed across three stages of the life cycle of forty-seven 3-digit manufacturing sectors. In the ‘early’ stage of the ILC, firm age is negatively correlated with hazard rates while firm productivity is not. Firm productivity is associated with lower hazard in the ‘mature’ stage of the ILC, when competition is primarily efficiency-driven, while firm age…
Empirical Equations for the Direct Definition of Stress–Strain Laws for Fiber-Section-Based Macromodeling of Infilled Frames
2018
Equivalent strut macromodels are largely used to model the influence of infill walls in frame structures due to their simplicity and effectiveness from a computational point of view. Despite these advantages, which are fundamental to carrying out seismic simulation of complex structures, equivalent struts are phenomenological models and therefore have to conventionally account for the influence of really large amounts of geometrical and mechanical variables with a relatively simple inelastic response. Mechanical approaches, generally used to evaluate the force-displacement curve of a strut, are based on hypothesizing the damage mechanism that will occur for an infill-frame system subject to…
Macroelement Model for the Progressive-Collapse Analysis of Infilled Frames
2021
A new multistrut macromodel for the analysis of the progressive-collapse response of infilled reinforced concrete (RC) frames is presented in this paper. The model consists of three struts: two outer infinitely rigid and resistant struts and one inner fiber-section strut. The inclination of the struts as well as the stress-strain response are modulated by two parameters that are obtained by means of analytical correlations provided in the paper. The latter link the geometric and mechanical properties of an infilled frame to the geometric configuration and mechanical response of the equivalent strut model. This confers the model the capability to adapt to consider different collapse configur…
A GRASP heuristic for the mixed Chinese postman problem
2002
Abstract Arc routing problems (ARPs) consist of finding a traversal on a graph satisfying some conditions related to the links of the graph. In the Chinese postman problem (CPP) the aim is to find a minimum cost tour (closed walk) traversing all the links of the graph at least once. Both the Undirected CPP, where all the links are edges that can be traversed in both ways, and the Directed CPP, where all the links are arcs that must be traversed in a specified way, are known to be polynomially solvable. However, if we deal with a mixed graph (having edges and arcs), the problem turns out to be NP -hard. In this paper, we present a heuristic algorithm for this problem, the so-called Mixed CPP…
The Hierarchical Mixed Rural Postman Problem: Polyhedral analysis and a branch-and-cut algorithm
2017
[EN] The Hierarchical Mixed Rural Postman Problem is defined on a mixed graph where arcs and edges that require a service are divided into clusters' that have to be serviced in a hierarchical order. The problem generalizes the Mixed Rural Postman Problem and thus is NP-hard. In this paper, we provide a polyhedral analysis of the problem and propose a branch-and-cut algorithm for its solution based on the introduced classes of valid inequalities. Extensive computational experiments are reported on benchmark instances. The exact approach allows to find the optimal solutions in less than 1 hour for instances with up to 999 vertices, 2678 links, and five clusters.
A practical framework for data management processes and their evaluation in population-based medical registries.
2013
We present a framework for data management processes in population-based medical registries. Existing guidelines lack the concreteness we deem necessary for them to be of practical use, especially concerning the establishment of new registries. Therefore, we propose adjustments and concretisations with regard to data quality, data privacy, data security and registry purposes.First, we separately elaborate on the issues to be included into the framework and present proposals for their improvements. Thereafter, we provide a framework for medical registries based on quasi-standard-operation procedures.The main result is a concise and scientifically based framework that tries to be both broad a…
Two-Dimensional Polytypism of “Crystalline” (C5Me5)ReO3
1996
Crystals of Cp*ReO3 present a rare case of two-dimensional polytypism. They consist of a polytypic packing (in the bc plane) of ordered polar chains of three-legged piano-stool Cp*ReO3 molecules (stacked head-to-tail along the a axis). The two-dimensional polytypism arises from the possibility of building a similar motif both with 2-fold screw axes and inversion centers as packing operators, i.e. from the possibility of packing together neighboring chains of equal or different polarity.
Input-Output Finite-Time Stability of Discrete-Time Impulsive Switched Linear Systems with State Delays
2013
Published version of an article in the journal: Circuits, Systems, and Signal Processing. Also available from the publisher at: http://dx.doi.org/10.1007/s00034-013-9610-7 This paper is concerned with the problem of input-output finite-time stability (IO-FTS) for discrete impulsive switched systems with state delays. Sufficient conditions are presented for the existence of IO-FTS for such systems under the cases of certain switching, arbitrary switching, and uncertain switching. All the obtained results are formulated in a set of linear matrix inequalities (LMIs). Two numerical examples are given to illustrate the effectiveness of the proposed results.
Generalized Dimension Distortion under Mappings of Sub-Exponentially Integrable Distortion
2010
We prove a dimension distortion estimate for mappings of sub-exponentially integrable distortion in Euclidean spaces, which is essentially sharp in the plane.
Variations on Weyl's theorem
2006
AbstractIn this note we study the property (w), a variant of Weyl's theorem introduced by Rakočević, by means of the localized single-valued extension property (SVEP). We establish for a bounded linear operator defined on a Banach space several sufficient and necessary conditions for which property (w) holds. We also relate this property with Weyl's theorem and with another variant of it, a-Weyl's theorem. We show that Weyl's theorem, a-Weyl's theorem and property (w) for T (respectively T*) coincide whenever T* (respectively T) satisfies SVEP. As a consequence of these results, we obtain that several classes of commonly considered operators have property (w).