Matrices

We investigated the effects of test anxiety on test performance using computerized adaptive testing (CAT) versus conventional fixed item testing (FIT). We hypothesized that tests containing mainly items with medium probabilities of being solved would have negative effects on test performance for testtakers high in test anxiety. A total of 110 students (aged 16 to 20) from a German secondary modern school filled out a short form of the Test Anxiety Inventory (TAI-G; Wacker, Jaunzeme, & Jaksztat, 2008) and then were presented with items from the Adaptive Matrices Test (AMT; Hornke, Etzel, & Rettig, 1999) on the computer, either in CAT form or in a fixed item test form with a selection of items arranged in order of increasing item difficulty. Additionally, half of the students were given a short summary of information about the mode of item selection in adaptive testing before working on the CAT. In a moderated regression approach, a significant interaction of test anxiety and test mode was revealed. The effect of test mode on the AMT score was stronger for students with higher scores on test anxiety than for students with lower test anxiety. Furthermore, getting information about CAT led to significantly better results than receiving standard test instructions. Results are discussed with reference to test fairness.

This study investigates how reliability (internal consistency) affects model-fitting in maximum likelihood exploratory factor analysis (EFA). This was accomplished through an examination of goodness of fit indices between the population and the sample matrices. Monte Carlo simulations were performed to create pseudo-populations with known parameters. Results indicated that the higher the internal consistency the worse the fit. It is postulated that the observations are similar to those from structural equation modeling where a good fit with low correlations can be observed and also the reverse with higher item correlations.

The problem of dimensionality with respect to Raven’s Advanced Progressive Matrices (APM) specifically and, more generally, g or fluid intelligence, has been a long-standing issue. The present article reports two studies examining the dimensionality of both the original Set II of the APM ( n = 506) and a short form ( n = 644), using principal component analysis and Rasch analysis. Although the results from the principal component analysis were equivocal, results from the Rasch analyses more strongly suggested that both forms of the test are best described as being multidimensional. Furthermore, comparison of items common to both forms indicated a context effect, thus making adaptive testing versions of this test difficult.

Abstract: In many testing situations, differential item functioning (DIF) is a potentially serious problem. It occurs when a test item appears to be easier for one group of examinees than another even after controlling for overall skill level. Differential person functioning (DPF) can occur when" items" can be considered raters and the persons are the objects being rated. This paper introduces the notion of DIF with object-rater data and transposed person-item matrices. The discussion only considers methods for DIF or DPF detection using a binary ...

T I. INTRODUCTION HIS paper deals with some mathematical aspects of the discrete Fourier transform (DFT), studied with linear algebra and matrix theory methods. The vast majority of papers on the DFT have concerned computational issues, most notably the extensive literature ...

It is now well-known that one can reconstruct sparse or compressible signals accurately from a very limited number of measurements, possibly contaminated with noise. This technique known as "compressed sensing" or "compressive sampling" relies on properties of the sensing matrix such as the restricted isometry property. In this note, we establish new results about the accuracy of the reconstruction from undersampled measurements which improve on earlier estimates, and have the advantage of being more elegant.

A good understanding of matrices and their properties is a necessary prerequisite for progress in almost any field within pure or applied mathematics, for example calculus in several variables, numerical analysis or control theory. This book is based on the course Matrix theory given at Lund University. It starts by recalling the basic theory of matrices and determinants, and then proceeds to more advanced subjects such as the Jordan Normal Form, functions of matrices, norms, normal matrices and singular values. The book may be used for a second course in linear algebra in a bachelor’s program in mathematics, or for a first year graduate course in engineering subjects. Distinguishing qualities compared with other texts on the subject are: The book starts gently compared with other texts with the same scope; There are many carefully worked out examples; It is possible to use the book for classes on different levels, by selecting parts of the material. The book contains a large number of exercises with answers, indication of difficulty and sometimes hints. The exercises are intended to help the students to think in new ways and to understand the art of proving mathematical statements.

To teach the rigorous skills and knowledge students need to succeed in future collegeentry courses and workforce training programs, education stakeholders have increasingly called for more rigorous curricula, instruction, and assessments. Identifying the critical attributes of rigor and measuring its appearance in curricular materials is therefore fundamental to progress in this area. By superposing two widely accepted models for describing rigor — Bloom's Taxonomy of Educational Objectives and Webb’s Depth-ofKnowledge (DOK) model — this article defines cognitive rigor (CR) and introduces the CR matrix for analyzing instruction and enhancing teacher lesson planning. Two large-scale collections of student work samples analyzed using the CR matrix are presented, illustrating the preponderance of curricular items aligned to each cell in the matrix. Educators should use the cognitive rigor matrix to align the content in their curricular materials to the instructional techniques used...

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Current geometric and solid modeling systems use semi-algebraic sets for de ning the boundaries of solid objects, curves and surfaces, geometric constraints with mating relationship in a mechanical assembly, physical contacts between objects, collision detection. It turns out that performing many of the geometric operations on the solid boundaries or interacting with geometric constraints is reduced to nding common solutions of the polynomial equations. Current algorithms in the literature based on symbolic, numeric and geometric methods su er from robustness, accuracy or e ciency problems or are limited to a class of problems only. In this paper we present algorithms based on multipolynomial resultants and matrix computations for solving polynomial systems. These algorithms are based on the linear algebra formulation of resultants of equations and in many cases there is an elegant relationship between the matrix structures and the geometric formulation. The resulting algorithm involves singular value decompositions, eigendecompositions, Gauss elimination etc. In the context of oating point computation their numerical accuracy is well understood. We also present techniques to make use of the structure of the matrices to improve the performance of the resulting algorithm and highlight the performance of the algorithms on di erent examples.

El uso de las Tecnologías de la Información y las Comunicaciones en la educación ha alcanzado mucho auge, su implementación en el proceso de enseñanza-aprendizaje es crucial. Un diagnóstico efectuado a los software educativos que se utilizan en la carrera de Ingeniería Informática e investigaciones actuales, confirman que existen limitaciones en la aprehensión del contenido del trabajo con matrices en la asignatura de Álgebra Lineal en los estudiantes del primer año de la carrera. Para dar solución al problema planteado, los autores se proponen como objetivo desarrollar un sistema informático para el aprendizaje del trabajo con matrices en la asignatura Álgebra Lineal de la carrera de Ingeniería Informática en la Universidad de Granma. Como resultado se obtuvo un tutorial para el aprendizaje del trabajo con matrices y la visualización paso a paso de la solución de los ejercicios, sustentado en los referentes teóricos de la comunicación, del desarrollo de recursos para la enseñanza semipresencial y modular con un alto componente colaborativo. El software se desarrolló con tecnologías como HTML 5, CSS 3, JavaScript, Bootstrap, jQuery y NetBeans. Se utilizó como metodología de desarrollo de software Extreme Programming (XP) que es una metodología ágil. Después del análisis, se comprueba la utilidad y fiabilidad del software que se obtiene, contribuyendo a la formación profesional de los estudiantes de la carrera de ingeniería y a mejorar el aprendizaje del trabajo con matrices.

This work presents an architecture to compute matrix inversions in a hardware reconfigurable FPGA using different floating-point representation precision: single, double and 40-bits. The architectural approach is divided into five principal parts, four modules and one unit, namely Change Row Module, Pivo Module, Matrix Elimination Module, Normalization Module and finally the Gauss-Jordan Control-Circuit Unit. This division allows the work with other smaller arithmetic units that are organized in order to maintain the accuracy of the results without the need to internally normalize and de-normalize the floatingpoint data. The implementation of the operations and the whole units take advantage of the resources available in the Virtex-5 FPGA. The error propagation and resource consumption of the implementation, specially the internal RAM memory blocks that are used, constitute improvements when compared with previous work of the authors and other more elaborated architectures whose implementations are significantly more complex than the current one and thus unsuitable for its application. The approach is validated by implementing benchmarks based on solutions in FPGA and software (e.g. Matlab) implemented previously.

Small matrices of calcium alginate or aluminium alginate have been investigated as possible controlled release systems for drugs. The objective of the present study was to sustain the release of theophylline from alginate matrices using different concentrations of aluminium chloride and calcium chloride in presence and absence of HPMC. Tablets containing differing concentrations of aluminium and calcium chloride were produced and the release rate of theophylline was tested using the basket dissolution apparatus over 8 h. Increasing amounts of aluminium chloride from 0.0001 to 0.00068 moles decreased the release of theophylline from 95.1 ± 0.27 to 29.5 ± 1.5, indicating a significant effect of aluminium ions on a reduction in the release rate of theophylline from sodium alginate matrices. In the case of matrices containing different concentrations of calcium ions, as the concentration of calcium chloride increased, the release rate increased to an optimum then declined after this. This was due to insufficient calcium ions being available to cross-link with the sodium alginate to form an insoluble gel. The effect of aluminium ions, as this is a trivalent ion compared to calcium, which is a divalent ion, aluminium ions are able to decrease the release rate with a smaller concentration compared to calcium ions. The results also showed that the presence of HPMC caused a reduction in release rate of theophylline from alginate matrices containing calcium chloride. Whereas, in the case of alginate matrices containing aluminium chloride the release rate of theophylline increased in presence of HPMC. For comparing the dissolution data, dissolution efficiency (DE) was used. The values of DE are consistent with the dissolution data. The results show that within a formulation series, DE values generally decrease when the cation concentration increases and this criterion can be used to describe the effect of calcium and aluminium ions on the release behaviour of theophylline from polymeric matrices.

In this paper, employing the general Doolittle factorization, an efficient algorithm is developed to find the inverse of a general pentadiagonal matrix which is suitable for implementation using computer algebra systems software such as Matlab and Maple. Examples are given to illustrate the efficiency of the algorithm.

The Raven Advanced Progressive Matrices Test (APM) is a well-known measure of higher order general mental ability. The time to administer the test, 40 to 60 minutes, is sometimes regarded as a drawback. To meet efficiency needs, the APM can be administered as a 30-or 40-minute timed test, or one of two developed short versions could be used. In this study, the 20-minute timed version of the APM is compared to the untimed APM as a measure of intellectual ability in 1st-year psychology students. This 20-minute timed version proves to be an adequate predictor of the untimed APM score.

Esta es una breve explicación del método de Gradiente Hidráulico propuesta por Todini y Pilati (1987), mediante la programación en el Lenguaje PYTHON 3.X, con el fin de compartirles y expandir el conocimiento sobre la programación orientada a la Ingeniería.

El propósito de este Cuaderno es detallar aspectos dinámicos e interactivos propios del análisis de datos cualitativos. El lector no encontrará en este Cuaderno únicamente aportes teórico-metodológicos sobre el proceso de análisis de los datos, sino también ejemplos detallados provenientes de nuestras propias experiencias de investigación en diversos proyectos que desarrollamos con sede en el Instituto de Investigaciones Gino Germani de la Facultad de Ciencias Sociales de la UBA. A través de ejemplos concretos buscamos dar cuenta del carácter no lineal del proceso de análisis cualitativo, y cómo éste se lleva a cabo en relación estrecha con las preguntas de investigación, la perspectiva conceptual y los métodos de investigación seleccionados. Estos aspectos del diseño son discutidos en el Capítulo 1. Los ejemplos incluidos en los Capítulos 2 y 3 permitirán a los lectores acceder a los procesos y decisiones que fueron tomando los investigadores al codificar y recodificar los datos, así como su experiencia en el armado de distintos tipos de despliegues visuales. La inclusión de ejemplos de investigaciones propias tiene además el propósito de dejar en claro que las estrategias y herramientas para el análisis cualitativo tienen que ser elaboradas ad-hoc para cada estudio particular.

La Universidad es fuente inagotable de producción de conocimiento para el desarrollo de la ciencia y la tecnología en el país, el diseño y creación de aplicaciones del área de computación y matemática requieren de una gran dedicación para el diseño, edición, simplificación, validación, y reutilización de código para la resolución de problemas que por su complejidad y extensión requieren de bibliotecas de métodos para facilitar la creación y mantenimiento de paquetes de aplicaciones con un mayor alcance en el área de estudio. Este trabajo tiene como objetivo, desarrollar una biblioteca de clases en java, para resolver problemas de computación y álgebra matricial mediante el uso de arreglos bidimensionales, que atienda a las necesidades de los docentes, investigadores y estudiantes de la Facultad de Ingeniería de la Universidad de Carabobo, como una  ayuda para el desarrollo de aplicaciones tomando como base el empleo de arreglos bidimensionales. Los rasgos importantes se determinaron a partir de fuentes tanto primarias como secundarias, que incluyeron, la observación directa y la aplicación de un instrumento de recolección de datos. Se utilizó un cuestionario estructurado con escala tipo Likert, para evaluar los aspectos que definen a la percepción que tiene el estudiante acerca de la implementación de los arreglos para la resolución de problemas prácticos de la ingeniería y la opinión de expertos en el área. Finalmente, esta investigación, busca definir las actividades básicas de programación de uso en la ingeniería para que la biblioteca, se pueda integrar como una herramienta de colaboración en la enseñanza por parte del profesorado y adicionalmente provea facilidades para futuros trabajos de investigación.

Tissue engineering is an exciting new cross-disciplinary methodology which applies the principles of engineering and structure-function relationships between normal and pathological tissues to develop biological substitute to restore, maintain or improve tissue function. Tissue engineering therefore involves a melange of approaches encompassing developmental biology, tissue mechanics, medicine, cell differentiation and survival biology, mechanostransduction and nano-fabrication technology. The central tissue of interest in this review is cartilage. Traumatic injuries, congenital abnormalities and age-related degenerative diseases can all lead to cartilage loss; however, the low cell density and very limited self-renewal capacity of cartilage necessitate the development of effective therapeutic repair strategies for this tissue. The ontogeny of the chondrocyte, which is the cell that provides the biosynthetic machinery for all the component parts of cartilage, is discussed, since an understanding of cartilage development is central to the maintenance of a chondrocytic phenotype in any strategy aiming to produce a replacement cartilage. A plethora of matrices have been developed for cartilage engineering approaches and many of these are discussed and their in vitro and in vivo applications covered in this review. Tissue engineering is entering an exciting era; significant advances have been made; however, many technical challenges remain to be solved before this technology becomes widely applicable across all areas of cartilage repair biology.

The relative proportions of genetically distinct collagen types in connective tissues vary with tissue type and change during disease progression, development, wound healing, aging. This study aims to 1) characterize the spectro-temporal fluorescence emission of fiber different types ...

Determinants are a function of the set of square matrices to the set of real numbers. The determinant of the matrix denote | A | or det (A). In this discussion method used to solve the determinant of a matrix is the Chio Condensation method. The Chio Condensation Method is one method that can be used to evaluating the determinant of the order matrix × , ≥ 3 determinant in terms of (− 1) × (− 1) with ≠ 0. Calculating the determinant of the matrix × , ≥ 3 with Chio Condensation method will be easier if it is assisted excel and Matlab.

Palette images are widely used on the World Wide Web (WWW) and in game-cartridge applications. Many images used on the WWW are stored and transmitted after they are compressed losslessly with the standard graphics interchange format (GIF), or portable network graphics (PNG). Well-known 2-D compression schemes, such as JPEG-LS and JPEG-2000, fail to yield better compression than GIF or PNG due to the fact that the pixel values represent indices that point to color values in a look-up table. To improve the compression performance of JPEG-LS and JPEG-2000 techniques, several researchers have proposed various reindexing algorithms. We investigate various compression techniques for color palette images. We propose a new technique comprised of a traveling salesman problem (TSP)-based reindexing scheme, Burrows-Wheeler transformation, and inversion ranks. We show that the proposed technique yields better compression gain on average than all the other 1-D compressors and the reindexing schemes that utilize JPEG-LS or JPEG-2000.