Search results for "Smooth"
showing 10 items of 710 documents
Adaptive smoothing spline using non-convex penalties
2022
We propose a new adaptive penalty for smoothing via penalized splines. The new form of adaptive penalization is based on penalizing the differences of the coefficients of adjacent bases, using non-convex penalties. This makes possible to estimate curves with varying amounts of smoothness. Comparisons with respect to some competitors are presented.
Real-time smoothing of car-following data through sensor-fusion techniques
2011
Abstract Observation of vehicles kinematics is an important task for many applications in ITS (Intelligent Transportation Systems). It is at the base of both theoretical analyses and application developments, especially in case of positioning and tracing/tracking of vehicles, car-following analyses and models, navigation and other ATIS (Advanced Traveller Information Systems), ACC (Adaptive Cruise Control) systems, CAS and CWS (Collision Avoidance Systems and Collision Warning Systems) and other ADAS (Advanced Driving Assistance Systems). Modern technologies supply low-cost devices able to collect time series of kinematic and positioning data with medium to very high frequency. Even more da…
Shape identification in inverse medium scattering problems with a single far-field pattern
2016
Consider time-harmonic acoustic scattering from a bounded penetrable obstacle $D\subset {\mathbb R}^N$ embedded in a homogeneous background medium. The index of refraction characterizing the material inside $D$ is supposed to be Holder continuous near the corners. If $D\subset {\mathbb R}^2$ is a convex polygon, we prove that its shape and location can be uniquely determined by the far-field pattern incited by a single incident wave at a fixed frequency. In dimensions $N \geq 3$, the uniqueness applies to penetrable scatterers of rectangular type with additional assumptions on the smoothness of the contrast. Our arguments are motivated by recent studies on the absence of nonscattering waven…
Leiomyoma of the hard palate : a case report
2007
Leiomyoma is a benign smooth muscle tumor that is very rarely located in the oral cavity. It is accepted that the smooth muscle giving rise to this tumor corresponds to the tunica media of the arteries. The tumor can develop at any age, with no clear gender predilection, and typically manifests as a slow-growing, asymptomatic lesion. The diagnosis is based on the histopathological study, with the use of specific staining techniques, including immunohistochemical markers. Treatment consists of complete resection of the lesion, with due safety margins. We present the case of a 57-year-old male with a tumor located for the previous four months in the region of the hard palate, adjacent to the …
Warning signalling in European vipers and their mimics : implications for conservation of the smooth snake
2014
Enhancing the Iterative Smoothed Particle Hydrodynamics Method
2021
Motivated by recent research on the iterative approach proposed for the smoothed particle hydrodynamics (ISPH) method, some ideas to improve the process are introduced. The standard procedure is enhanced iterating on the residuals preserving the matrix-free nature of the process. The method is appealing providing reasonable results with disordered data distribution too and no kernel variations are needed in the approximation. This work moves forward with a novel formulation requiring a lower number of iterations to reach a desired accuracy. The computational procedure is described and some results are introduced to appreciate the proposed formulation.
Splines in convex sets under constraints of two‐sided inequality type in a hyperplane
2008
The problem of minimization of a smoothing functional under inequality constraints is considered in a hyperplane. The conditions of the existence of a solution are obtained and some properties of this solution are investigated. It is proved that the solution is a spline. The method for its construction is suggested. First Published Online: 14 Oct 2010
Estimating aggregated nutrient fluxes in four Finnish rivers via Gaussian state space models
2013
Reliable estimates of the nutrient fluxes carried by rivers from land-based sources to the sea are needed for efficient abatement of marine eutrophication. Although nutrient concentrations in rivers generally display large temporal variation, sampling and analysis for nutrients, unlike flow measurements, are rarely performed on a daily basis. The infrequent data calls for ways to reliably estimate the nutrient concentrations of the missing days. Here, we use the Gaussian state space models with daily water flow as a predictor variable to predict missing nutrient concentrations for four agriculturally impacted Finnish rivers. Via simulation of Gaussian state space models, we are able to esti…
The induced smoothed LASSO
2016
We propose a new lasso-type estimator of regression coefficients for regression models. Our proposal relies on the recent idea of induced smoothing and leads to estimators with sampling distribution somewhat close to the Normal one, regardless of their true value, along with the corresponding reliable covariance matrix. As a consequence inference (e.g. p-values) may be carried out relatively easily. We present results from some simulation experiments.
Are the Growth Standards of the World Health Organization Valid for Spanish Children? The SONEV Study
2021
Background: The use of different growth tables to assess the population's nutritional status has given rise to a series of limitations arising from the lack of consensus and uniform methodological criteria. This leads to a disparity of results that prevent an accurate and reliable diagnosis of whether a child is overweight or obese.Objective: The purpose of this study was to develop growth references for weight, height, and body mass index for Eastern-Spanish children from 6 to 16 years of age.Methods: The final sample used to fit the growth curves was made up of 1,102 observations. The 2007 WHO curves are currently used for Child Health Service Cards. Therefore, to make the comparison of t…