Search results for "Criterion"
showing 10 items of 171 documents
EXPERIMENTAL STUDY ON THE FLUID FLOWIN THE CONDUCTS
2018
Fluids are high mobility environments that, under the action of external forces, are continuously and irreversibly deformed. The flow of fluid through a pipe is ensured by a pressure difference between its ends. The presented paper aims to experimentally determine the velocity profile of flowing a Newtonian fluid through a circular section pipe by measuring the local speed at five points on the pipe radius.
Applied Mathematics versus Fluid Dynamics
2018
This paper investigates scientific, institutional, and political conflict and collaboration between two different disciplines in the first part of the 20th century: applied mathematics and fluid dynamics. It argues for the catalytic role of Richard von Mises (1883–1953) in this process and analyzes the reasons for von Mises’s considerable fame in the former and limited posthumous reputation in the latter field. I argue that von Mises’s contributions to fluid dynamics and aerodynamics suffered chiefly from two somewhat interconnected deficiencies compared to the work of his principal competitors. There was, on the one hand, von Mises’s methodological preference for applied mathematics as opp…
Molecular Clustering of Phenylurea Herbicides: Comparison with Sulphonylureas, Pesticides and Persistent Organic Pollutants
2014
Chromatographic retention times of phenylurea herbicides are modelled by structure–property relationships. Properties are hydration free energy and dipole. Bioplastic evolution is an evolutionary perspective conjugating the effect of acquired characters and relations that emerge among evolutionary indeterminacy, morphological determination and natural selection principles. Classification algorithms are proposed based on information entropy and production. Phenylureas are classified by Cl2, O2 and N2 presence; their different behaviour depends on the number of Cl atoms. When applying procedures to moderate-sized sets, excessive results appear compatible with data and suffer a combinatorial e…
Validation of a Modified Version of the Psychological Capital Questionnaire (PCQ12) in Spain
2018
Background : Previous studies have found some limitations and inconsistencies in the functioning of the short Psychological Capital Questionnaire (PCQ12), suggesting the need to improve it. The objective of the current study is to validate a modified version of the PCQ12 in Spain. Method : The sample consists of 792 employees from 42 Spanish organizations. A cross-validation was carried out to test the factorial validity of the modified scale. Reliability and convergent, discriminant, and criterion validity were also tested. Results : The modified PCQ12 showed good psychometric qualities. A four-factor structure showed a better fit to the data than the original second-order structure. Conc…
The impact of study design and diagnostic approach in a large multi-centre ADHD study: Part 2: Dimensional measures of psychopathology and intelligen…
2011
Contains fulltext : 97437.pdf (Publisher’s version ) (Open Access) BACKGROUND: The International Multi-centre ADHD Genetics (IMAGE) project with 11 participating centres from 7 European countries and Israel has collected a large behavioural and genetic database for present and future research. Behavioural data were collected from 1068 probands with ADHD and 1446 unselected siblings. The aim was to describe and analyse questionnaire data and IQ measures from all probands and siblings. In particular, to investigate the influence of age, gender, family status (proband vs. sibling), informant, and centres on sample homogeneity in psychopathological measures. METHODS: Conners' Questionnaires, St…
Systematic review and critical appraisal of Childhood Trauma Questionnaire - Short Form (CTQ-SF).
2021
Abstract Background Child maltreatment is a complex and multidimensional construct that encompasses a great number of risk factors. The Childhood Trauma Questionnaire — Short Form, one of the most widely used and validated instruments to assess childhood maltreatment in the past ten years, is a retrospective instrument that assesses several types of childhood abuse and maltreatment which is divided into five dimensions. Objective The objectives of this systematic review are to critically appraise, compare, and summarize the methodological quality and psychometric properties of published research articles validating the Childhood Trauma Questionnaire — Short Form utilizing the COSMIN checkli…
Optical state engineering, quantum communication, and robustness of entanglement promiscuity in three-mode Gaussian states
2006
We present a novel, detailed study on the usefulness of three-mode Gaussian states states for realistic processing of continuous-variable quantum information, with a particular emphasis on the possibilities opened up by their genuine tripartite entanglement. We describe practical schemes to engineer several classes of pure and mixed three-mode states that stand out for their informational and/or entanglement properties. In particular, we introduce a simple procedure -- based on passive optical elements -- to produce pure three-mode Gaussian states with {\em arbitrary} entanglement structure (upon availability of an initial two-mode squeezed state). We analyze in depth the properties of dist…
Multipartite entanglement in three-mode Gaussian states of continuous variable systems: Quantification, sharing structure and decoherence
2005
We present a complete analysis of multipartite entanglement of three-mode Gaussian states of continuous variable systems. We derive standard forms which characterize the covariance matrix of pure and mixed three-mode Gaussian states up to local unitary operations, showing that the local entropies of pure Gaussian states are bound to fulfill a relationship which is stricter than the general Araki-Lieb inequality. Quantum correlations will be quantified by a proper convex roof extension of the squared logarithmic negativity (the contangle), satisfying a monogamy relation for multimode Gaussian states, whose proof will be reviewed and elucidated. The residual contangle, emerging from the monog…
AQM generalized nyquist stability in multiple bottleneck networks
2005
Abstract The influence of multiple bottlenecks on the stability of Active Queue Management (AQM) controllers, usually configured on a single bottleneck basis is discussed. We consider a network scenario where RED is configured at each router according to previously developed control theoretic techniques. These configuration rules assure stability in a single bottleneck scenario. We show that instability may arise when two links become congested. We justify this result through a multiple bottleneck model using the Generalized Nyquist stability criterion.
Energetic criterion of the error evaluation in the analysis via SGBEM
2006
The Symmetric Galerkin Boundary Element Method (sGbem) is assuming more and more an effective role in the solving problems of mechanics in different fields of engineering [1]. The presence of symmetric and defined in sign algebraic operators make such Method more competitive in comparison to the formulation for collocation. The present work has as objective the improvement of the response in the process of analysis of the system where a first discretizazion has been operated, by using a strategy that allows to operate a estimate of the error. On the base of such estimate it is possible to operate a new discretizazion of the boundary through adaptive procedures.