Search results for "ORIENTATION"
showing 10 items of 1041 documents
L'orientation, un rouage important dans la genèse des inégalités sociales à l'école
1989
National audience
Les inégalités sociales à l'école : la théorie sociologique à l'épreuve des faits
1998
International audience; L'auteur esquisse une analyse de la manière dont les principales données factuelles concernant les inégalités sociales à l'école peuvent être éclairées par deux grandes perspectives théoriques : l'une met en avant l'héritage culturel familial plus ou moins adapté aux exigences de l'école, l'autre explique les choix en matière d'options et d'orientations comme les résultats de calculs rationnels effectués par des "acteurs stratèges".
Les choix d'orientation des élèves sont-ils les vecteurs des inégalités sociales ?
1999
International audience
Backward spin polarizabilityγπof the proton
2002
Using the Mainz $48\mathrm{cm}\ensuremath{\emptyset}\ifmmode\times\else\texttimes\fi{}64\mathrm{cm}$ NaI(Tl) detector and the segmented G\"ottingen recoil detector SENECA in coincidence, Compton scattering by the proton at ${\ensuremath{\theta}}_{\ensuremath{\gamma}}^{\mathrm{lab}}=136\ifmmode^\circ\else\textdegree\fi{}$ has been measured at MAMI (Mainz) in the energy range from 200 to 470 MeV. The new data confirm the previous observation that there is a systematic discrepancy between MAMI and LEGS (Brookhaven) data leading to different spin polarizabilities ${\ensuremath{\gamma}}_{\ensuremath{\pi}}=\ensuremath{-}38.7\ifmmode\pm\else\textpm\fi{}1.8$ and $\ensuremath{-}27.2\ifmmode\pm\else\…
Sensorless variable speed single-phase induction motor drive system based on direct rotor flux orientation
2012
The single-phase induction motor (SPIM) is one of the electrical machines more used in the World, and can be found in several fractional and sub-fractional horsepower applications in houses, offices, shoppings, farms, and industries. The introduction of more sophisticated applications has required the use of variable speed drives for SPIM, where the adoption of sensorless techniques is the more reasonable option for speed control due to the low cost of this electrical machine. A proposal for sensorless variable speed SPIM drive based on direct rotor field orientation techniques is presented in this paper. None transformation is used in order to eliminate the asymmetry of the stator windings…
Sensorless variable speed single-phase induction motor drive system
2012
It is usual find single-phase induction motor (SPIM) in several house, office, shopping, farm, and industry applications, which are become each time more sophisticated and requiring variable speed drives. Considering the low cost of this machine, the adoption of sensorless speed control is the more reasonable option for SPIM drives. This paper presents a proposal for sensorless variable speed SPIM drive based on direct rotor field orientation techniques. An observer based on two independent linear close-loop control systems provides the estimation of the rotor flux and speed from the measurements of the stator currents and voltages. These estimatives are used by close-loop systems for speed…
The exploratory factor analysis of items: guided analysis based on empirical data and software
2017
El objetivo del presente trabajo es ilustrar cómo la aplicación adecuada o inadecuada del análisis factorial exploratorio (AFE) puede llevar a conclusiones muy diferentes. Para ello se evalúa el grado en que cuatro paquetes estadísticos diferentes que permiten realizar AFE de ítems, en concreto SPSS, FACTOR, PRELIS y MPlus, permiten o limitan la aplica- ción de los estándares actualmente recomendados en materia de análisis factorial. Asimismo se analizan y comparan los resultados que ofrecen di- chos programas cuando se factorizan datos empíricos de escalas que ajus- tan, según el caso, de manera inadecuada, ambigua u óptima a los supuestos del modelo AFE lineal clásico, a través de las dis…
Educación para la innovación agraria. Un modelo para la acción educativa
2019
[ES] Este estudio se centra en la figura del productor agrario valenciano y su comportamiento frente a la innovación. Adoptar una postura proclive a la innovación depende de múltiples factores que influyen en la gestión de la empresa agraria. Este estudio utiliza los datos procedentes de una encuesta a productores agrarios valencianos, diseñada ad hoc para la investigación, que profundiza en los factores socioeconómicos que pueden decantar al productor agrario hacia una postura favorable a la innovación. Posteriormente, el estudio se centra en obtener un perfil tipo que caracteriza al productor según sus características y las de su explotación, según su actitud innovadora y la orientación h…
Endoscopic surgery of the rhinobasis with a computer-assisted localizer
1996
The endoscope is useful for the diagnosis and surgical therapy of diseases of the nose, the paranasal sinuses and its neighboring regions, and allows for microinvasive, functional approaches. The reduced invasiveness of therapeutic procedures is sometimes accompanied by insufficient clearness of the surgical field, however. This significant problem is solved by the computer-assisted-surgery (CAS) system, an intraoperative localizer. It allows continuous orientation based on three-dimensional reconstructed preoperative CT scans with superimposed positioning of the endoscope. We have now adapted CAS for endoscopic sinus surgery, which meant that a variety of visualization methods were tested.…
High-Definition Imaging in Spinal Neuroendoscopy
2010
BACKGROUND Spinal endoscopy is still under controversial discussion. An often acclaimed critic is the poor endoscopic image quality in comparison with the microscope. Since high-definition digital cameras have recently been introduced into spinal neuroendoscopy, the aim of the current study is to examine whether superior image quality has a relevant impact on intraoperativen orientation. MATERIAL AND METHODS A lumbar endoscopic discectomy was recorded simultaneously in High-Definition resolution (HD) and Standard-Definition resolution (SD). 10 experienced spinal surgeons were asked to identify predefined as well as not predefined anatomic structures in HD and SD resolution. Additionally, th…