1,090 research outputs found
Application of composite spectrum in agricultural machines
Producción CientíficaComposite spectrum (CS) is a data-fusion technique that reduces the number of spectra to be analyzed, simplifying the analysis process for machine monitoring and fault detection. In this work, vibration signals from five components of a combine harvester (thresher, chopper, straw walkers, sieve box, and engine) are obtained by placing four accelerometers along the combine-harvester chassis in non-optimal locations. Four individual spectra (one from each accelerometer) and three CS (non-coherent, coherent and poly-coherent spectra) from 18 cases are analyzed. The different cases result from the combination of three working conditions of the components—deactivated (off), balanced (healthy), and unbalanced (faulty)—and two speeds—idle and maximum revolutions per minute (RPM). The results showed that (i) the peaks can be identified in the four individual spectra that correspond to the rotational speeds of the five components in the analysis; (ii) the three formulations of the CS retain the relevant information from the individual spectra, thereby reducing the number of spectra required for monitoring and detecting rotating unbalances within a combine harvester; and, (iii) data noise reduction is observed in coherent and poly-coherent CS with respect to the non-coherent CS and the individual spectra. This study demonstrates that the rotating unbalances of various components within agricultural machines, can be detected with a reduced number of accelerometers located in non-optimal positions, and that it is feasible to simplify the monitoring with CS. Overall, the coherent CS may be the best composite spectra formulation in order to monitor and detect rotating unbalances in agricultural machines
A Simple Method to Improve Autonomous GPS Positioning for Tractors
Error is always present in the GPS guidance of a tractor along a desired trajectory. One way to reduce GPS guidance error is by improving the tractor positioning. The most commonly used ways to do this are either by employing more precise GPS receivers and differential corrections or by employing GPS together with some other local positioning systems such as electronic compasses or Inertial Navigation Systems (INS). However, both are complex and expensive solutions. In contrast, this article presents a simple and low cost method to improve tractor positioning when only a GPS receiver is used as the positioning sensor. The method is based on placing the GPS receiver ahead of the tractor, and on applying kinematic laws of tractor movement, or a geometric approximation, to obtain the midpoint position and orientation of the tractor rear axle more precisely. This precision improvement is produced by the fusion of the GPS data with tractor kinematic control laws. Our results reveal that the proposed method effectively reduces the guidance GPS error along a straight trajectory.regional 2010 Research Project Plan of the Junta de Castilla y León, (Spain), under project VA034A10-2. It was also partially supported by the 2009 ITACyL project entitled ―Realidad aumentada, Bci y correcciones RTK en red para el guiado GPS de tractores (ReAuBiGPS
Utilización de programas CAM para el aprendizaje de la asignatura Fabricación y Máquinas
Póster presentado en: VIII Jornadas de Innovación Docente de la UBU, Burgos, 5 de abril de 2016, organizadas por el Instituto de Formación e Innovación Educativa-IFIE de la Universidad de Burgo
RBF-Neural network applied to the quality classification of tempered 100Cr6 steel cams by the multi-frequency nondestructive eddy current testing
Producción CientíficaThis article proposes a Radial Basis Function Artificial Neural Network (RBF-ANN) to classify tempered steel cams as correctly or incorrectly treated pieces by using multi-frequency nondestructive eddy current testing. Impedances at five frequencies between 10 kHz and 300 kHz were employed to perform the binary sorting. The ANalysis Of VAriance (ANOVA) test was employed to check the significance of the differences between the impedance samples for the two classification groups. Afterwards, eleven classifiers were implemented and compared with one RBF-ANN classifier: ten linear discriminant analysis classifiers and one Euclidean distance classifier. When employing the proposed RBF-ANN, the best performance was achieved with a precision of 95% and an area under the Receiver Operating Characteristic (ROC) curve of 0.98. The obtained results suggest RBF-ANN classifiers processing multi-frequency impedance data could be employed to classify tempered steel DIN 100Cr6 cams with a better performance than other classical classifiers
Desarrollo de un modelo de eventos discretos en Matlab para la operación óptima de centros de proceso de datos
En este proyecto se va a tratar de modelar un Centro de Procesamiento de Datos (CPD) o Data Centers, para asi poder ver su comportamiento cuando este esta sometido a varias alteraciones externas manipulables o no.
La función de todo este proyecto es que a base de un modelado de eventos discretos consiga simularse con suficiente precisión el funcionamiento de un CPD, para así poder mejorar la eficiencia energética del mismo en un futuro.In this project we will try to model a Data Center so that we can see its behavior when it is exposed to several manipulable external alterations or not.
The function of this whole project is that, based on a modeling of discrete events, the operation of a Data Center can be simulated with enough precision, in order to improve its energy efficiency in the future.Universidad de Sevilla. Grado en Ingeniería de Organización Industria
Strong coupling between weakly guided semiconductor nanowire modes and an organic dye
The light-matter coupling between electromagnetic modes guided by a semiconductor nanowire and excitonic states of molecules localized in its surrounding media is studied from both classical and quantum perspectives, with the aim of describing the strong-coupling regime. Weakly guided modes (bare photonic modes) are found through a classical analysis, identifying those lowest-order modes presenting large electromagnetic fields spreading outside the nanowire while preserving their robust guided behavior. Experimental fits of the dielectric permittivity of an organic dye that exhibits excitonic states are used for realistic scenarios. A quantum model properly confirms through an avoided mode crossing that the strong-coupling regime can be achieved for this configuration, leading to Rabi splitting values above 100 meV. In addition, it is shown that the coupling strength depends on the fraction of energy spread outside the nanowire, rather than on the mode field localization. These results open up a new avenue towards strong-coupling phenomenology involving propagating modes in nonabsorbing media.The authors acknowledge the Spanish Ministerio de Economía, Industria y Competitividad for financial support through Grants No. MAT2014-53432-C5-5-R, No. FIS2015-69295-C3-2-P, and No. FIS2017-91413-EXP; the María de Maeztu program for Units of Excellence in R&D (MDM-2014-0377); and an FPU Fellowship (D.R.A.) and a Ramón y Cajal grant (J.F.). We also acknowledge funding from the European Research Council (ERC-2016-STG-714870
Lessons learned on home energy monitoring and management: Smartcity Málaga
The Smartcity Málaga project is one of Europe?s largest ecoefficient city initiatives. The project has implemented a field trial in 50 households to study the effects of energy monitoring and management technologies on the residential electricity consumption. This poster presents some lessons learned on energy consumption trends, smart clamps reliability and the suitability of power contracted by users, obtained after six months of data analysis
The Puerto Lapice eucrite fall phenomenon
The fall of the Pu
erto Lápice eucrite
occurred in the afternoon of May 10, 2007,
17h57m20±2s UTC. This impressive daylight bolide
was witnessed by thousands of people from Spain, and
is being carefully studied in the framework of the
Spanish Meteor and Fireball Network (SPMN) in a
similar way that we previously did after the fall of the
Villalbeto de la Peña L6 or
dinary chondrite [1,2]. Unfortunately, there is no video records to our knowledge
of the Puerto Lápice even
t, but some eyewitnesses
were able to take pictures of the persistent train from at
least two different locations. Nocturn astrometric calibrations from both places have been obtained, and
these data together with
in situ
trajectory measurements with theodolite of casual eyewitnesses have allowed to estimate the atmo
spheric trajectory and the
radiant with reasonable accu
racy. A preliminary trajectory reconstruction by the SPMN obtained only two
weeks after the event helped
to recover the first meteorite specimens. The meteorite was presented on June
11, 2007 during the International Conference Meteoroids 2007 in Barcelona. In addition to the fall phenomena, the interest of this bolide lies in the eucrite nature
of the recovered meteorite,
that has been recently reported in the Meteoritical Bulletin [3]. Of the 200
eucrites known until 2000, only 25 correspond to observed falls, but the fall circumstances are poorly
known except in few remarkable cases like e.g. Pasamonte
Figuras de ancho constante: un tema por explorar
El objetivo de este artículo es describir algunos métodos de construcción de figuras de ancho constante en el entorno Cabri Geometry II Plus; tales métodos son producto de un estudio sobre algunas propiedades y la historia de figuras con esta característica. Pretendemos, específicamente, presentar un contexto que provee información sucinta de propiedades básicas. Exponemos métodos de construcción que las generan describiendo los caminos que se utilizaron para deducirlos; además, mostramos algunas aplicaciones que se les han dado a las figuras de ancho constante en contextos matemáticos que favorecen la construcción de otro tipos de figuras, a saber, curvas de Zindler
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