Publications

Displaying 1076 - 1100 of 1227

Publication	Date
Non-Linear Random Wave Groups With a Superimposed Current Authors: Felice Arena,Vincenzo Nava,Alessandra Romolo In this paper a new solution for non-linear random wave groups in the presence of a uniform current is obtained, by extending to the second-order the Boccotti’s ‘Quasi-Determinism’ (QD) theory. The second formulation of the QD theory gives the mechanics of linear random wave groups when a large… ASMEDC	2006-01-01
On the vertical wind shear of Saturn's Equatorial Jet at cloud level Authors: Agustín Sánchez-Lavega,Santiago Pérez-Hoyos Abstract In this work we analyze and compare the vertical cloud structure of Saturn's Equatorial Zone in two different epochs: the first one close to the Voyagers flybys (1979–1981) and the second one in 2004, when the Cassini spacecraft entered its orbit around the planet. Our goal is to… Elsevier BV	2006-01-01
A 2D and 3D hp-Finite Element Method for Simulation of Through Casing Resistivity Logging Instruments Authors: Carlos Torres-Verdín,Leszek Demkowicz,David Pardo In order to avoid collapse of wells in oil fields, the use of steel casing has been a common technique throughout the last decades. However, the casing of a well with a steel pipe has some undesired effects. For instance, the assessment of electrical properties of the rock formation becomes more… IEEE	2006-01-01
Integration of hp-adaptivity and a two-grid solver for elliptic problems Authors: David Pardo,Leszek Demkowicz We present implementation details and analyze convergence of a two-grid solver forming the core of the fully automatic hp-adaptive strategy for elliptic problems. The solver delivers a solution for a fine grid obtained from an arbitrary coarse hp-grid by a global hp-refinement. The classical V-… Elsevier BV	2006-01-01
Evaluating and optimizing the parameters of an unsupervised graph-based WSD algorithm Authors: Oier Lopez de Lacalle,Aitor Soroa,Eneko Agirre,David Martinez Veronis (2004) has recently proposed an innovative unsupervised algorithm for word sense disambiguation based on small-world graphs called HyperLex. This paper explores two sides of the algorithm. First, we extend Veronis' work by optimizing the free parameters (on a set of words which is different… Association for Computational Linguistics (ACL)	2006-01-01
Pointwise convergence of solutions to the nonelliptic Schr\"odinger equation Authors: Keith M. Rogers,Luis Vega González,Ana María Vargas Rey It is conjectured that the solution to the Schrodinger equation in R n+1 converges almost everywhere to its initial datum f, for all f ∈ H s (R n ), if and only if s ≥ 1 4. It is known that there is an s < 1 2 for which the solution converges for all f ∈ H s (R 2 ). We show that the solution… Indiana University Mathematics Journal	2006-01-01
Two‐Dimensional High‐Accuracy Simulation of Resistivity Log ging‐While‐Drilling (LWD) Measurements Using a Self‐Adaptiv e Goal‐Oriented $hp$ Finite Element Method Authors: Maciej Paszyński,Maciej Paszyński,Carlos Torres-Verdín,David Pardo,Leszek Demkowicz We simulate electromagnetic (EM) measurements acquired with a logging‐while‐drilling (LWD) instrument in a borehole environment. The measurements are used to assess electrical properties of rock formations. Logging instruments as well as rock formation properties are assumed to exhibit axial… Society for Industrial & Applied Mathematics (SIAM)	2006-01-01
Responsiveness and clinically important differences for the WOMAC and SF-36 after hip joint replacement Authors: Quintana, J.M.,Escobar, A.,Bilbao, A.,Arostegui, I.,Lafuente, I.,Vidaurreta, I. To study responsiveness and establish the minimal clinically important differences (MCID) and minimal detectable change (MDC) in patients undergoing total hip replacement (THR) using the Short Form 36 (SF-36) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).We… Elsevier BV	2005-12-01
Variable coefficient Schrödinger flows for ultrahyperbolic operators Authors: Kenig, C.E.,Ponce, G.,Rolvung, C.,Vega, L. In this paper we study the local solvability of nonlinear Schr��dinger equations of the form $$\p_t u = i {\cal L}(x) u + \vec b_1(x)\cdot \nabla_x u + \vec b_2(x)\cdot \nabla_x \bar u + c_1(x)u+c_2(x)\bar u +P(u,\bar u,\nabla_x u, \nabla_x\bar u), where $x\in\mathbb R^n$, $t>0$, $\displaystyle… Elsevier BV	2005-10-01
Verification of goal-oriented HP-adaptivity Authors: Paszyński, M.,Demkowicz, L.,Pardo, D. The paper presents calculations for the radiation of a loop antenna wrapped around a metallic cylinder into a conductive medium. The problem has been solved analytically by using Fourier transform and Bessel functions. The analytical solution has been used to verify a goal-oriented hp adaptive… Elsevier BV	2005-10-01
Asymmetric Joint Source-Channel Coding for Correlated Sources with Blind HMM Estimation at the Receiver Authors: Ser, Javier Del,Crespo, Pedro M,Galdos, Olaia We consider the case of two correlated sources, S1 and S2. The correlation between them has memory, and it is modelled by a hidden Markov chain. The paper studies the problem of reliable communication of the information sent by the source S1 over an additive white Gaussian noise (AWGN) channel when… Springer Science and Business Media LLC	2005-09-08
Parallel and Multi-Objective EDAs to Create Multivariate Calibration Models for Quantitative Chemical Applications Authors: Jose Miguel-Alonso,C. Ubide,Jose A. Lozano,Alexander Mendiburu,M. Ostra This paper describes the application of several data mining approaches to solve a calibration problem in a quantitative chemistry environment. Experimental data obtained from reactions which involve known concentrations of two or more components are used to calibrate a model that, later, will be… IEEE	2005-08-03
Parallel Implementation of EDAs Based on Probabilistic Graphical Models Authors: Jose A. Lozano,Alexander Mendiburu,Jose Miguel-Alonso This paper proposes new parallel versions of some estimation of distribution algorithms (EDAs). Focus is on maintenance of the behavior of sequential EDAs that use probabilistic graphical models (Bayesian networks and Gaussian networks), implementing a master-slave workload distribution for the… Institute of Electrical and Electronics Engineers (IEEE)	2005-08-01
Jupiter's 24° N highest speed jet: Vertical structure deduced from nonlinear simulations of a large-amplitude natural disturbance Authors: Agustín Sánchez-Lavega,Timothy E. Dowling,Enrique Garcia-Melendo Abstract The evolution of a large-amplitude disturbance at cloud level in Jupiter's 24° N jet stream in 1990 is used to constrain the vertical structure of a realistic atmospheric model down to the 6 bar pressure level. We use the EPIC model (Dowling et al., 1998, The explicit planetary… Elsevier BV	2005-08-01
Saturn's cloud structure and temporal evolution from ten years of Hubble Space Telescope images (1994–2003) Authors: Agustín Sánchez-Lavega,Richard G. French,Santiago Pérez-Hoyos,Jose Félix Rojas Abstract We present a study of the vertical structure of clouds and hazes in the upper atmosphere of Saturn's Southern Hemisphere during 1994–2003, about one third of a Saturn year, based on Hubble Space Telescope images. The photometrically calibrated WFPC2 images cover the spectral region… Elsevier BV	2005-07-01
Influence of age and gender on quality-of-life outcomes after cholecystectomy Authors: V. Oribe,B. Barrios,I. Garay,Inmaculada Arostegui,José M. Quintana,I. López de Tejada Few studies have assessed the role of sociodemographic characteristics on outcomes after a cholecystectomy. Our goal was to evaluate the influence of age and gender on the health related quality of life (HRQoL) changes after cholecystectomy in this prospective observational study of consecutive… Springer Science and Business Media LLC	2005-04-01
Editorial Introduction Special Issue on Estimation of Distribution Algorithms Authors: Jose A. Lozano,P. Larra Naga MIT Press - Journals	2005-03-01
Translation and psychometric testing of the Basque version of the SF-36 Health Survey Authors: I. Crespo,Angel Padierna,Inmaculada Arostegui,Nerea González,M. A. Vesga,José M. Quintana,E. Martínez The primary goals of this study were to adapt the Short Form-36 (SF-36) questionnaire to the Basque language and to assess the translated questionnaire's psychometric properties.Two pilot studies and a field study were conducted in 1999. The pathologies selected were hypertension, eating disorders… Springer Science and Business Media LLC	2005-03-01
Jupiter's cyclones and anticyclones vorticity from Voyager and Galileo images Authors: Agustín Sánchez-Lavega,Jon Legarreta Abstract We have measured the internal velocity field in jovian synoptic-scale cyclones and anticyclones by tracking cloud elements in very high spatial resolution images obtained by the Voyager 1 and 2 (in 1979) and Galileo (1996–2000) spacecrafts. In total we have studied 24 different closed… Elsevier BV	2005-03-01
How Long Is the Day on Saturn? Authors: Agustín Sánchez-Lavega Determining a planet's rotation period can be difficult if the planet lacks a solid surface. However, for planets with an internal magnetic field, emissions at radio wavelengths are modulated by the planet's rotation rate. The latest results from the Cassini spacecraft seem to indicate that Saturn'… American Association for the Advancement of Science (AAAS)	2005-02-25
Health-Related Quality of Life and Appropriateness of Cholecystectomy Authors: José Ma Quintana,Mercedes Varona,Inmaculada Arostegui,Luis Perdigo,Amaia Bilbao,José Luis Cabriada,Victor Oribe To evaluate the relationship among appropriateness of the use of cholecystectomy and outcomes.The use of cholecystectomy varies widely across regions and countries. Explicit appropriateness criteria may help identify suitable candidates for this commonly performed procedure. This study evaluates… Ovid Technologies (Wolters Kluwer Health)	2005-01-01
Comparison of GPS/SAC-C and MIPAS/ENVISAT Temperature Profiles and Its Possible Implementation for EOS MLS Observations Authors: Norbert Glatthor,Gabriele Stiller,T. Steck,Thomas von Clarmann,Gizaw Mengistu Tsidu,Michael J. Schwartz,Michael Höpfner,Chi O. Ao,Manuel López-Puertas,Bernd Funke,Mathias Milz,Herbert Fischer,Jonathan H. Jiang,D. Y. Wang,Andrea Linden,Larry L. Romans,… This analysis presents comparisons of the atmospheric temperatures retrieved from GPS/SAC-C radio occultation observations using the JPL retrieval software, and from MIPAS/ENVISAT infrared spectrum measurements using the IMK data processor. Both individual profiles and zonal means of the… Springer Berlin Heidelberg	2005-01-01
A variable step size LMS algorithm for the suppression of the CPR artefact from a VF signal Authors: A. Lazkano,Elisabete Aramendi,Unai Irusta,Jesus Ruiz,José Julio Gutiérrez,S.R. de Gauna Artefacts created by thoracic compressions during cardiopulmonary resuscitation (CPR) prevent the proper classification of the cardiac rhythm by an automatic external defibrillator (AED), making a pause in CPR necessary for a correct rhythm analysis. Previously proposed adaptive filtering methods… IEEE	2005-01-01
Comparisons of MIPAS/ENVISAT and GPS-RO/CHAMP Temperatures Authors: Thomas von Clarmann,Andrea Linden,Gizaw Mengistu Tsidu,Mathias Milz,Georg Beyerle,Michael Höpfner,Manuel López-Puertas,Michael Kiefer,Jens Wickert,D. Y. Wang,Herbert Fischer,Gabriele Stiller,Torsten Schmidt,Sylvia Kellmann,Norbert Glatthor,Bernd Funke,… The temperatures retrieved from MIPAS/ENVISAT limb mid-infrared emission and CHAMP GPS radio occultation measurements are compared at altitudes between 8 – 30 km during the stratospheric major sudden warming in the southern hemisphere winter of 2002. The mean differences between the correlative… Springer Berlin Heidelberg	2005-01-01
Cross comparisons of O3 and NO2 measured by the atmospheric ENVISAT instruments GOMOS, MIPAS, and SCIAMACHY Authors: Horst Fischer,C. von Savigny,Mark Weber,Andrea Linden,Norbert Glatthor,D. Y. Wang,Astrid Bracher,Martin Kaufmann,G. Mengistu Tsidu,Manuel López-Puertas,J. Skupin,Klaus Bramstedt,Vladimir Rozanov,T. Steck,Michael Höpfner,Sergio Gil-Lopez,Mathias Milz,Kai-… Vertical profiles of O3 and NO2 abundances from the atmospheric instruments GOMOS (Global Ozone Monitoring by the Occultation of Stars), MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) and SCIAMACHY (Scanning Imaging Spectrometer for Atmospheric Chartography) all on-board the… Elsevier BV	2005-01-01