BIRD, BCAM's Institutional Repository DataThe BIRD digital repository system captures, stores, indexes, preserves, and distributes digital research material.http://bird.bcamath.org:802018-01-18T16:01:07Z2018-01-18T16:01:07ZWildland fire propagation modeling: fire-spotting parametrisation and energy balanceEgorova V. N.Pagnini G.Trucchia A.http://hdl.handle.net/20.500.11824/7602018-01-13T02:00:10Z2017-07-04T00:00:00ZWildland fire propagation modeling: fire-spotting parametrisation and energy balance
Egorova V. N.; Pagnini G.; Trucchia A.
Present research concerns the physical background of a wild-fire propagation model
based on the split of the front motion into two parts - drifting and fluctuating. The drifting part is solved by the level set method and the fluctuating part describes turbulence
and fire-spotting. These phenomena have a random nature and can be modeled as a
stochastic process with the appropriate probability density function. Thus, wildland fire
propagation results to be described by a nonlinear partial differential equation (PDE) of
the reaction-diffusion type. A numerical study of the effects of the atmospheric stability
on wildfire propagation is performed through its effects on fire-spotting. Moreover, it
is shown that the solution of the PDE as an indicator function allows to construct the
energy balance equation in terms of the temperature.
2017-07-04T00:00:00ZSuper Abrasive Machining of Integral Rotary Components Using Grinding Flank ToolsGonzález H.Calleja A.Pereira O.Ortega N.Lopez de Lacalle N.Bartoň M.http://hdl.handle.net/20.500.11824/7592018-01-12T08:24:42Z2018-01-01T00:00:00ZSuper Abrasive Machining of Integral Rotary Components Using Grinding Flank Tools
González H.; Calleja A.; Pereira O.; Ortega N.; Lopez de Lacalle N.; Bartoň M.
Manufacturing techniques that are applied to turbomachinery components represent a challenge in the aeronautic sector. These components require high resistant super-alloys in order to satisfy the extreme working conditions they have to support during their useful life. Besides, in the particular case of Integrally Bladed Rotors (IBR), usually present complex geometries that need
to be roughed and finished by milling and grinding processes, respectively. In order to improve their manufacturing processes, Super Abrasive Machining (SAM) is presented as a solution because it combines the advantages of the use of grinding tools with milling feed rates. However, this innovative technique usually needed high tool rotary speed and pure cutting oils cooling. These
issues implied that SAM technique was not feasible in conventional machining centers. In this work, these matters were tackled and the possibility of using SAM in these five-axis centers with emulsion coolants was achieved. To verify this approach, Inconel 718 single blades with non-ruled surfaces were manufactured with Flank-SAM technique and conventional milling process, analyzing cutting forces, surface roughness, and dimension accuracy in both cases. The results show that SAM implies a suitable, controllable, and predictable process to improve the manufacture of aeronautical critical components, such as IBR.
2018-01-01T00:00:00ZBilinear representation theoremLi K.Martikainen H.Ou Y.Vuorinen E.http://hdl.handle.net/20.500.11824/7582018-01-08T02:00:09Z2018-01-01T00:00:00ZBilinear representation theorem
Li K.; Martikainen H.; Ou Y.; Vuorinen E.
We represent a general bilinear Calderón--Zygmund operator as a sum of simple dyadic operators. The appearing dyadic operators
also admit a simple proof of a sparse bound. In particular, the representation implies a so called sparse $T1$ theorem for bilinear singular integrals.
2018-01-01T00:00:00ZBootstrap-based procedures for inference in nonparametric receiver-operating characteristic curve regression analysisRodríguez-Álvarez M.X.Roca-Pardiñas J.Cadarso-Suárez C.Tahoces P.G.http://hdl.handle.net/20.500.11824/7572017-12-23T02:00:11Z2017-01-01T00:00:00ZBootstrap-based procedures for inference in nonparametric receiver-operating characteristic curve regression analysis
Rodríguez-Álvarez M.X.; Roca-Pardiñas J.; Cadarso-Suárez C.; Tahoces P.G.
Prior to using a diagnostic test in a routine clinical setting, the rigorous evaluation of its diagnostic accuracy is essential.
The receiver-operating characteristic curve is the measure of accuracy most widely used for continuous diagnostic tests.
However, the possible impact of extra information about the patient (or even the environment) on diagnostic accuracy also
needs to be assessed. In this paper, we focus on an estimator for the covariate-specific receiver-operating characteristic
curve based on direct regression modelling and nonparametric smoothing techniques. This approach defines the class of
generalised additive models for the receiver-operating characteristic curve. The main aim of the paper is to offer new
inferential procedures for testing the effect of covariates on the conditional receiver-operating characteristic curve within
the above-mentioned class. Specifically, two different bootstrap-based tests are suggested to check (a) the possible effect of
continuous covariates on the receiver-operating characteristic curve and (b) the presence of factor-by-curve interaction
terms. The validity of the proposed bootstrap-based procedures is supported by simulations. To facilitate the application of
these new procedures in practice, an R-package, known as npROCRegression, is provided and briefly described. Finally,
data derived from a computer-aided diagnostic system for the automatic detection of tumour masses in breast cancer is
analysed
2017-01-01T00:00:00Z