Dispersionless integrable systems in 3D and Einstein-Weyl geometry

For several classes of second order dispersionless PDEs, we show that the symbols of their formal linearizations define conformal structures which must be Einstein-Weyl in 3D (or self-dual in 4D) if and only if the PDE is integrable by the method of hydrodynamic reductions. This demonstrates that the integrability of these dispersionless PDEs can be seen from the geometry of their formal linearizations.Comment: In this version we add Preliminary Section and the Appendix, where we discuss the geometry of PDEs and the method of hydrodynamic reductions. Also we add Lax pairs for the 5 integrable equations of type I, and supply the ancillary files (Maple verifications of the calculations, Maple and Mathematica form of Integrability Conditions, together with their PDF versions) for completenes

Inner Regions and Interval Linearizations for Global Optimization

International audienceResearchers from interval analysis and constraint (logic) programming communities have studied intervals for their ability to manage infinite solution sets of numerical constraint systems. In particular, inner regions represent subsets of the search space in which all points are solutions. Our main contribution is the use of recent and new inner region extraction algorithms in the upper bounding phase of constrained global optimization. Convexification is a major key for efficiently lower bounding the objective function. We have adapted the convex interval taylorization proposed by Lin & Stadtherr for producing a reliable outer and inner polyhedral approximation of the solution set and a linearization of the objective function. Other original ingredients are part of our optimizer, including an efficient interval constraint propagation algorithm exploiting monotonicity of functions. We end up with a new framework for reliable continuous constrained global optimization. Our interval B&B is implemented in the interval-based explorer Ibex and extends this free C++ library. Our strategy significantly outperforms the best reliable global optimizers

Nonlinear Kinetic and Equilibrium Adsorption Isotherm Study of Cadmium (II) Sorption by Dacryodes edulis Biomass

The kinetics and equilibrium adsorption isotherm of cadmium (II) adsorption onto Dacryodes edulis (native peer seed) biomass was studied using a nonlinear approach, which is unpopular but proven in some literature to be more reliable and easier. In optimizing the process, about 98% removal of the cadmium ion was achieved within five minutes at pH 7 by contacting just 30 mg of the Dacryodes edulis seed biomass with the adsorbate solution of a concentration of 100 mg/L. Non-linear investigation of the kinetics and adsorption isotherms of the process was done using the R console statistical and computing software. The results indicated that the Elovich mechanism and the Freundlich adsorption isotherm most suitably described the kinetics and adsorption isotherm, respectively, of the process as provided by their least values of the sum of squared residuals (SSR). This outcome implied a chemical adsorption  (chemisorption) mechanism and a multi-layer coverage by the cadmium ions on heterogeneous active sites of the biomass surface with a Freundlich constant or capacity factor, Kf of 27.83 mg g-1, heterogeneity factor, 1/n of 0.2614 and Elovich constants, α and β of 7.0 mg g−1 s−1 and 1.0 g mg-1, respectively. These findings indicate that Dacryodes edulis seed biomass has a good potential for cadmium (II) adsorption. Keywords: Dacryodes edulis, Elovich kinetic model, Freundlich isotherm, Langmuir isotherm, Nonlinear&nbsp

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 320)

This bibliography lists 125 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during January, 1989. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 355)

This bibliography lists 147 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during October, 1991. Subject coverage includes: aerospace medicine and psychology, life support systems and controlled environments, safety equipment, exobiology and extraterrestrial life, and flight crew behavior and performance

Dispersionless integrable systems in 3D and Einstein-Weyl geometry

For several classes of second order dispersionless PDEs, we show that the symbols of their formal linearizations define conformal structures which must be Einstein- Weyl in 3D (or self-dual in 4D) if and only if the PDE is integrable by the method of hydrodynamic reductions. This demonstrates that the integrability of these dispersionless PDEs can be seen from the geometry of their formal linearizations

Implementation of PPP as new GNSS Observation Type in the Geomonitoring System GOCA

[EN] Early detection of significant movements in both natural and artificial structures is crucial to prevent human, environmental and economic losses. For this reason, Geomonitoring in an active field. GNSS technics are also a filed in which lot of research and improvement have been made in recent years. Some studies have indicated the potential of GNSS technics in the field of Geomonitoring. The aim of this master thesis is developing a software that allows processing GNSS data with Precise Point Positioning technic in the context of the geomonitoring project GOCA. With this implementation, potential of PPP with low cost receiver (U-Blox ZED-F9P) using different products and settings is evaluated in this document. Based on a literature review, that includes the study of GOCA project and a summary of main PPP approaches, a C++ dialog-based software was design and developed, using RTKLIB and WaPPP as software engines. Besides that, two different observations were made (one 12 hours to post-processing and one real time) in order to test the developed software and evaluate the obtained results using different parameters or products. The obtained results reaffirm the potential of the PPP technique, even using low cost receiver. Even some differences between different software engines or IGS products were found, the results allow us to conclude that PPP is a technique with many advantages in the field of geomonitoring, since it avoids the use of several receivers and good accuracies are obtained. However, some aspects need further research in this context, as there is no common criterion for establishing convergence time and new methodologies and algorithms are being developed in the field of PPP processing.[ES] La detección temprana de movimientos significativos en estructuras naturales y artificiales es crucial para prevenir pérdidas humanas, ambientales y económicas. Por esta razón, Geomonitorización es un campo activo. Las técnicas de GNSS son también un campo en el que se han realizado muchas investigaciones y mejoras en los últimos años. Algunos estudios han indicado el potencial de las técnicas GNSS en el campo de la geomonitorización. El objetivo de esta tesis de máster es desarrollar un software que permita el procesamiento de datos GNSS con la técnica de posicionamiento de punto preciso en el contexto del proyecto de geomonitorización GOCA. Con esta implementación, el potencial del PPP con el receptor de bajo coste (U-Blox ZED-F9P) usando diversos productos y configuraciones se va a evalúar en este documento. Basado en una revisión de la literatura, que incluye el estudio del proyecto GOCA y un resumen de los principales enfoques PPP, se diseñó y desarrolló un software basado en diálogos C++, utilizando RTKLIB y WaPPP como motores de software. Además, se realizaron dos observaciones diferentes (una de 12 horas para el post-procesamiento y otra en tiempo real) con el fin de probar el software desarrollado y evaluar los resultados obtenidos utilizando diferentes parámetros o productos. Los resultados obtenidos reafirman el potencial de la técnica PPP, incluso utilizando un receptor de bajo coste. Incluso habiendo encontrado algunas diferencias entre diferentes motores de software o productos IGS, los resultados nos permiten concluir que PPP es una técnica con muchas ventajas en el campo de la geomonitorización, ya que evita el uso de varios receptores y se obtienen buenas precisiones. Sin embargo, algunos aspectos necesitan más investigación en este contexto, ya que no existe un criterio común para establecer el tiempo de convergencia y se están desarrollando nuevas metodologías y algoritmos en el campo del procesamiento PPP.Luján García Muñoz, R. (2020). Implementation of PPP as new GNSS Observation Type in the Geomonitoring System GOCA. http://hdl.handle.net/10251/139668TFG

Site Amplification and Attenuation via Downhole Array Seismogram Inversion: A Comparative Study of the 2003 Miyagi-Oki Aftershock Sequence

Weak-motion geotechnical array recordings at 38 stations of the Japanese strong-motion network KiK-Net from the 2003 M_w 7:0 Miyagi-Oki aftershock sequence are used here to quantify the amplification and attenuation effects of near-surface formations to incident seismic motion. Initially, a seismic waveform optimization algorithm is implemented for the evaluation of high-resolution, low-strain velocity (V_s), attenuation (Q_s), and density (ρ) profiles at the sites of interest. Based on the inversion results, V_s versus Q_s correlations are developed, and scattering versus intrinsic attenuation effects are accounted for in their physical interpretation. Surface-to-downhole traditional spectral ratios (SSR), cross-spectral ratios (c-SSR), and horizontal-to-vertical (H/V) site-response estimates are next evaluated and compared, while their effectiveness is assessed as a function of the site conditions classified on the basis of the weighted average Vs of the upper 30 m (V_(s30)) of the formations. Single and reference-station site-response estimates are successively compared to surface-to-rock outcrop amplification spectra and are evaluated by deconvolution of the downhole records based on the inversion results; comparison of the observed SSR and estimated surface-to-rock outcrop amplification spectra illustrates the effects of destructive interference of downgoing waves at the downhole instrument level as a function of the site class. Site amplification factors are successively computed in reference to the National Earthquake Hazards Reduction Program (NEHRP) B–C boundary site conditions (V_(s30) = 760 m/sec), and results are compared to published values developed on the basis of strong-motion data and site-response analyses. Finally, weak-motion SSR estimates are compared to the mainshock spectra, and conclusions are drawn for the implications of soil nonlinearity in the near surface. Results presented in this article suggest that currently employed site classification criteria need to be reevaluated to ensure intraclass consistency in the assessment of amplification potentials and nonlinearity susceptibility of near-surficial soil formations

On improving the performance of the Gauss-Newton filter

Includes abstract.Includes bibliographical references.The Gauss-Newton filter is a tracking filter developed by Norman Morrison around the same time as the celebrated Kalman filter. It received little attention, primarily due to the computation requirements at the time. Today computers have vast processing capacity and computation is no-longer an issue. The filter finite memory length is identified as the key element in the Gauss-Newton filter adaptability and robustness. This thesis focuses on improving the performance of the Gauss-Newton. We incorporate the process noise statistics into the filter algorithm to obtain a filter which explains the error covariance inconsistency of the Kalaman filter. In addition, a biased version of the linear Gauss-Newton filter, with lower mean squared error than the unbiased filter, is proposed. Furthermore the Gauss-Newton filter is adapted using the Levenberg Marquardt method for improved convergence. In order to improve the computation requirements, a recursive version of the filter is obtained