Search results for "linear"
showing 10 items of 7165 documents
Comparing the Climatic and Landscape Risk Factors for Lyme Disease Cases in the Upper Midwest and Northeast United States
2020
Lyme disease, recognized as one of the most important vector-borne diseases worldwide, has been increasing in incidence and spatial extend in United States. In the Northeast and Upper Midwest, Lyme disease is transmitted by Ixodes scapularis. Currently, many studies have been conducted to identify factors influencing Lyme disease risk in the Northeast, however, relatively few studies focused on the Upper Midwest. In this study, we explored and compared the climatic and landscape factors that shape the spatial patterns of human Lyme cases in these two regions, using the generalized linear mixed models. Our results showed that climatic variables generally had opposite correlations with Lyme d…
A posteriori error identities for nonlinear variational problems
2015
A posteriori error estimation methods are usually developed in the context of upper and lower bounds of errors. In this paper, we are concerned with a posteriori analysis in terms of identities, i.e., we deduce error relations, which holds as equalities. We discuss a general form of error identities for a wide class of convex variational problems. The left hand sides of these identities can be considered as certain measures of errors (expressed in terms of primal/dual solutions and respective approximations) while the right hand sides contain only known approximations. Finally, we consider several examples and show that in some simple cases these identities lead to generalized forms of the …
Estimates for the Differences of Certain Positive Linear Operators
2020
The present paper deals with estimates for differences of certain positive linear operators defined on bounded or unbounded intervals. Our approach involves Baskakov type operators, the kth order Kantorovich modification of the Baskakov operators, the discrete operators associated with Baskakov operators, Meyer&ndash
Strategic and motivational factors as predictors of pre-service primary teachers's success in problem solving
2014
En este trabajo se presenta una investigación descriptiva que muestra las relaciones entre cinco factores motivacionales y estratégicos (planificación, estrategias cognitivas, autocontrol, esfuerzo y autoeficacia) y el rendimiento en la resolución de problemas. Se administró a 66 maestras y maestros de primaria en formación un cuadernillo con dos problemas (problema 1 y problema 2) y el test de O'Neil y Schacter. Los resultados de los análisis de regresión múltiple ponen de manifiesto que: a) planificación, esfuerzo y autoeficacia son predictores significativos de las puntuaciones de las puntuaciones del problema de estructura simple (problema 1); b) esfuerzo, autoeficacia y estrategias cog…
Recensione di: M. Pavanello, “Il segreto degli antenati. Un etnografo nel cuore del Ghana”
2008
Recensione di: M. Pavanello, “Il segreto degli antenati. Un etnografo nel cuore del Ghana”
Revista electrónica de investigación y evaluación educativa
2014
Resumen tomado de la publicación Título, resumen y palabras clave en inglés y español Se muestra que cuando se quiere conocer el grado de satisfacción del alumno con la docencia recibida, es aconsejable introducir en su análisis y estudio componentes contextuales. Las variables contextuales que se incluyen en el análisis están relacionadas con determinadas estructuras académicas de carácter organizativo. Estas estructuras son de tipo jerárquico o anidado y aportan información sobre datos como el tipo de estudios que el alumno realiza o la clase en la que el alumno está matriculado. Para obtener el nivel de satisfacción del alumnado se utilizan los cuestionarios de evaluación docente de la U…
The Influence of Student Abilities and High School on Student Growth: A Case Study of Chinese National College Entrance Exam
2019
Enabled by available educational data and data mining techniques, educational data analysis has become a hot topic. Current researches mainly focus on the prediction of problems and performance rather than revealing the underlying causal relationships. Based on a unique exam data, we extracted the abilities of examinee from HSEE (High School Entrance Exam) based on the knowledge of educational experts, then we measured student growth from middle school to high school in total score and subject scores. We studied the impact of high school ranking and student abilities of HSEE on student growth by multiple linear regression model, in which high school ranking is divided into 5 levels, Level 1…
APROXIMACIÓN CONCEPTUAL Y PRÁCTICA A LOS MODELOS DE ECUACIONES ESTRUCTURALES
2017
En el presente trabajo se expone una aproximación conceptual y práctica a los Modelos de Ecuaciones Estructurales o Structural Equation Modeling (SEM). Los SEM están considerados entre las herramientas más potentes para el estudio de relaciones causales en datos no experimentales. Son una combinación del análisis factorial y la regresión múltiple y están compuestos por dos componentes: el modelo de medida y el modelo estructural. El modelo de medida describe la relación existente entre una serie de variables observables; mientras que en el modelo estructural se especifican las relaciones hipotetizadas entre las variables, es decir, se describen las relaciones entre las variables latentes me…
A Nonlinear Control of Synchronous Reluctance Motors (SynRM) Based on Feedback Linearization Considering the Self and Cross-Saturation Effects
2019
This paper proposes a nonlinear controller based on feedback linearization for Synchronous Reluctance Motors (SynRM) drives that takes into consideration the self and cross-saturation effects. Such control technique permits the dynamics of both the speed and flux loops to be maintained constant independently from the load and the saturation of the iron core. The proposed technique has been tested experimentally on a suitably developed test set-up.
Non-linear interactions of femtosecond laser pulses with graphene : photo-oxidation, imaging and photodynamics
2017
This thesis presents a study focused on interactions of femtosecond laser pulses with graphene, a one atom thick carbon membrane. Graphene, which exhibits exceptional electronic and optoelectronic properties, could provide considerable advantage over current silicon-based electronics. Graphene alone, being semi-metal, is not sufficient for electronic applications, but requires modification. For this, a set of methods for modifying and measuring the properties of graphene was developed. With the perspective of making graphene a suitable component for electronics, optoelectronics or photonics, ultrashort laser pulses were used for drawing patterns on graphene. The procedure modifies graphene …