Search results for "STATISTICS"
showing 10 items of 7671 documents
Domain-Specific Characteristics of Data Quality
2017
The research discusses the issue how to describe data quality and what should be taken into account when developing an universal data quality management solution. The proposed approach is to create quality specifications for each kind of data objects and to make them executable. The specification can be executed step-by-step according to business process descriptions, ensuring the gradual accumulation of data in the database and data quality checking according to the specific use case. The described approach can be applied to check the completeness, accuracy, timeliness and consistency of accumulated data.
El efecto mediador y moderador de la internacionalización en la relación entre los sistemas de control de gestión y el compromiso con la innovación
2019
La literatura contable revela resultados contradictorios al evaluar el efecto que los diferentes usos de los sistemas de control de gestión (SCG) tienen en la innovación. Siguiendo el marco teórico establecido por Simons (1995), este trabajo prueba el efecto que la internacionalización, bien sea directo, mediador o moderador, tiene en la relación entre el uso interactivo de los SCG y el compromiso de las empresas con la innovación. Tomando una muestra de 231 organizaciones del sector agroalimentario español, los resultados obtenidos ponen de manifiesto la ausencia de una relación directa entre el uso interactivo del conjunto de herramientas de SCG y el compromiso con la innovación. Del mism…
A Geometric Algorithm for Ray/Bézier Surfaces Intersection Using Quasi-Interpolating Control Net
2008
In this paper, we present a new geometric algorithm to compute the intersection between a ray and a rectangular Bezier patch. The novelty of our approach resides in the use of bounds of the difference between a Bezier patch and its quasi-interpolating control net. The quasi-interpolating polygon of a Bezier surface of arbitrary degree approximates the limit surface within a precision that is function of the second order difference of the control points, which allows for very simple projections and 2D intersection tests to determine sub-patches containing a potential intersection. Our algorithm is simple, because it only determines a 2D parametric interval containing the solution, and effici…
MILES extended: Stellar population synthesis models from the optical to the infrared
2016
We present the first single-burst stellar population models which covers the optical and the infrared wavelength range between 3500 and 50000 Angstrom and which are exclusively based on empirical stellar spectra. To obtain these joint models, we combined the extended MILES models in the optical with our new infrared models that are based on the IRTF (Infrared Telescope Facility) library. The latter are available only for a limited range in terms of both age and metallicity. Our combined single-burst stellar population models were calculated for ages larger than 1 Gyr, for metallicities between [Fe/H] = -0.40 and 0.26, for initial mass functions of various types and slopes, and on the basis …
Searching for the right timing of surgical delay: angiogenesis, vascular endothelial growth factor and perfusion changes in a skin-flap model.
2009
Summary Background The angiogenic potential of vascular endothelial growth factor (VEGF) and its oxygen pressure-dependent regulation suggest a strong connection between this growth factor and the ‘delay phenomenon'. In this study we focused on the chronological changes in VEGF concentration and flap perfusion in order to optimise the duration of surgical delay. Methods The VEGF concentration in skin and underlying muscle was measured in oversized, random-pattern flaps on 38 male Sprague-Dawley rats after 3, 5 or 7 days of surgical delay. Additionally, flaps were raised 5 or 7 days past preconditioning. The effect on flap perfusion was measured using indocyanine green fluoroscopy and the si…
Human T cells in silico: Modelling their electrophysiological behaviour in health and disease
2016
Although various types of ion channels are known to have an impact on human T cell effector functions, their exact mechanisms of influence are still poorly understood. The patch clamp technique is a well-established method for the investigation of ion channels in neurons and T cells. However, small cell sizes and limited selectivity of pharmacological blockers restrict the value of this experimental approach. Building a realistic T cell computer model therefore can help to overcome these kinds of limitations as well as reduce the overall experimental effort. The computer model introduced here was fed off ion channel parameters from literature and new experimental data. It is capable of simu…
How credit ratings affect sovereign credit risk: cross-border evidence in Latin American emerging markets
2017
This article builds upon previous literature by providing a better understanding of how contagion changes in bordering sovereign CDS emerging markets resulting from credit rating events. To that end, we follow the novel GVAR methodology using data from six Latin American emerging countries during an extensive sample period from 2004 to 2014. Our findings show evidence for the existence of significant and asymmetric cross-border effects. In particular, a competition effect is observed before the event occurs, indicating that non-event countries suffer (benefit) from upgrades (downgrades) in Brazil, Mexico and Chile (in Argentina and Brazil). In contrast, an imitation effect is observed after…
Evaluating several satellite precipitation estimates and global ground-based dataset on Sicily (Italy)
2012
The developing of satellite-based precipitation retrieval systems, presents great potentialities for several ap plications ranging from weather and meteorological applications to hydrological modelling. Evaluating perfor mances for these estimates is essential in order to understand their real capabilities and suitability related to each application. In this study an evaluation analysis of satellite precipitation retrieval systems has been carried out for the area of Sicily (Italy). Sicily is an island in the Mediterranean sea with a particular climatology and morphology, which is considered as an interesting test site for satellite precipitation products on the European mid-latitude area…
Noise-induced behavioral change driven by transient chaos
2022
We study behavioral change in the context of a stochastic, non-linear consumption model with preference adjusting, interdependent agents. Changes in long-run consumption behavior are modelled as noise induced transitions between coexisting attractors. A particular case of multistability is considered: two fixed points, whose immediate basins have smooth boundaries, coexist with a periodic attractor, with a fractal immediate basin boundary. If a trajectory leaves an immediate basin, it enters a set of complexly intertwined basins for which final state uncertainty prevails. The standard approach to predicting transition events rooted in the stochastic sensitivity function technique due to Mil…
Explaining Individual and Collective Programming Students’ Behavior by Interpreting a Black-Box Predictive Model
2021
Predicting student performance as early as possible and analysing to which extent initial student behaviour could lead to failure or success is critical in introductory programming (CS1) courses, for allowing prompt intervention in a move towards alleviating their high failure rate. However, in CS1 performance prediction, there is a serious lack of studies that interpret the predictive model’s decisions. In this sense, we designed a long-term study using very fine-grained log-data of 2056 students, collected from the first two weeks of CS1 courses. We extract features that measure how students deal with deadlines, how they fix errors, how much time they spend programming, and so forth. Subs…