An O(N) Algorithm for Three-Dimensional N-Body Simulations

We develop an algorithm that computes the gravitational potentials and forces on N point-masses interacting in three-dimensional space. The algorithm, based on analytical techniques developed by Rokhlin and Greengard, runs in order N time. In contrast to other fast N-body methods such as tree codes, which only approximate the interaction potentials and forces, this method is exact ?? computes the potentials and forces to within any prespecified tolerance up to machine precision. We present an implementation of the algorithm for a sequential machine. We numerically verify the algorithm, and compare its speed with that of an O(N2) direct force computation. We also describe a parallel version of the algorithm that runs on the Connection Machine in order 0(logN) time. We compare experimental results with those of the sequential implementation and discuss how to minimize communication overhead on the parallel machine.

Three-Dimensional Motion Estimation Using Shading Information in Multiple Frames

A new formulation for recovering the structure and motion parameters of a moving patch using both motion and shading information is presented. It is based on a new differential constraint equation (FICE) that links the spatiotemporal gradients of irradiance to the motion and structure parameters and the temporal variations of the surface shading. The FICE separates the contribution to the irradiance spatiotemporal gradients of the gradients due to texture from those due to shading and allows the FICE to be used for textured and textureless surface. The new approach, combining motion and shading information, leads directly to two different contributions: it can compensate for the effects of shading variations in recovering the shape and motion; and it can exploit the shading/illumination effects to recover motion and shape when they cannot be recovered without it. The FICE formulation is also extended to multiple frames.

Two-dimensional Photonic Crystals Fabricated by Nanoimprint Lithography

We report on the process parameters of nanoimprint lithography (NIL) for the fabrication of two-dimensional (2-D) photonic crystals. The nickel mould with 2-D photonic crystal patterns covering the area up to 20mm² is produced by electron-beam lithography (EBL) and electroplating. Periodic pillars as high as 200nm to 250nm are produced on the mould with the diameters ranging from 180nm to 400nm. The mould is employed for nanoimprinting on the poly-methyl-methacrylate (PMMA) layer spin-coated on the silicon substrate. Periodic air holes are formed in PMMA above its glass-transition temperature and the patterns on the mould are well transferred. This nanometer-size structure provided by NIL is subjective to further pattern transfer.

Exploring Bit-Difference for Approximate KNN Search in High-dimensional Databases

In this paper, we develop a novel index structure to support efficient approximate k-nearest neighbor (KNN) query in high-dimensional databases. In high-dimensional spaces, the computational cost of the distance (e.g., Euclidean distance) between two points contributes a dominant portion of the overall query response time for memory processing. To reduce the distance computation, we first propose a structure (BID) using BIt-Difference to answer approximate KNN query. The BID employs one bit to represent each feature vector of point and the number of bit-difference is used to prune the further points. To facilitate real dataset which is typically skewed, we enhance the BID mechanism with clustering, cluster adapted bitcoder and dimensional weight, named the BID⁺. Extensive experiments are conducted to show that our proposed method yields significant performance advantages over the existing index structures on both real life and synthetic high-dimensional datasets.

Learning Three-Dimensional Shape Models for Sketch Recognition

Artifacts made by humans, such as items of furniture and houses, exhibit an enormous amount of variability in shape. In this paper, we concentrate on models of the shapes of objects that are made up of fixed collections of sub-parts whose dimensions and spatial arrangement exhibit variation. Our goals are: to learn these models from data and to use them for recognition. Our emphasis is on learning and recognition from three-dimensional data, to test the basic shape-modeling methodology. In this paper we also demonstrate how to use models learned in three dimensions for recognition of two-dimensional sketches of objects.

Dimensional structure of the Brief Symptom Inventory with Spanish college students. 'Estructura dimensional del Brief Symptom Inventory con universitarios espa??oles'

Resumen tomado de la publicaci??n. Resumen tambi??n en ingl??s

Propiedades psicom??tricas y estructura dimensional de la adaptaci??n espa??ola del Cuestionario de Estrategias de Afrontamiento en Competici??n Deportiva

Resumen tomado de la publicaci??n

Una aproximación a las actitudes políticas de los españoles mediante una estructura dimensional inductiva

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Psychometric Properties of the Inventário Dimensional Clínico da Personalidade (IDCP) using the Rating Scale Model

The aim of this study was to evaluate the performance of the Dimensional Clinical Personality Inventory (DCPI) using Rasch-based person and item analysis. 1281 participants were recruited, between 18 and 90 years of age (M=26.64; SD=8.94), 431 men (33.6%) and 127 (9.9%) patients diagnosed with axis I disorders and/or axis II according to DSM-IV-TR. Results indicated the IDCP scales performed reasonably well, and the usefulness of the analyses presented, demonstrate the Rasch model’s applicability for clinical applications. Among the important tools offered by the Rasch model, we explore the use of the person-item map, which visually presents the intuitively understandable psychological construct along the dimensional scale of the instrument.

Psicopatía: una perspectiva dimensional y no penal del constructo

La personalidad psicopática tiene un innegable vínculo histórico con el comportamiento antisocial, con un predominio de los estudios latinoamericanos con muestras de los centros penitenciarios. Sin embargo, nuevos resultados han sugerido que los comportamientos antisociales, por su falta de especificidad, no deben considerarse como un elemento central para el constructo psicopatía, lo que permite su estudio en la población general. Así, el objetivo de este estudio es presentar una revisión de la literatura sobre el tema de la psicopatía, con énfasis en los estudios que aportan evidencia a favor de una visión dimensional y no penal del constructo. Se revisan las relaciones con el comportamiento antisocial, los resultados de investigaciones taxométricas, relaciones con narcisismo y maquiavelismo y con la teoría Reinforcement Sensitivity. Se sugiere la investigación del constructo en la población general en América Latina y la construcción o adaptación de instrumentos adecuados para esto propósito.

Metrología dimensional.

En el libro se desarrollan 16 capítulos: Unidades, Errores, Causas de error, Equipos de medida, Patrones, Normalización de ajustes, Medida de redondez, Control del acabado superficial, Mediciones de longitud, Medidas por comparación, Medida de ángulos, Medida de conos y radios de cilindros y esferas, Planitud y rectitud, Verificación de engranajes, Verificación de roscas, y Verificación de las máquinas herramientas. Al finalizar el último capítulo se ofrece un vocabulario de los términos metrológicos más significativos, relacionados con los temas de: magnitudes y unidades, mediciones, resultados de medición, instrumentos de medida, características de los instrumentos de medida y patrones.

Problemas sobre metrología dimensional.

La obra plantea una serie de cien problemas solucionados, seleccionados como los más significativos de los siguientes temas: Unidades (problemas 1-2-3), Dilataciones (p. 4-5-6-7-8-9-10), Errores (p. 11-12-13), Sensibilidades (p. 14-15-16-17-18), Ajustes y Tolerancias (p. 19-20-21-22-23-24-25-26-27-28), Redondez (p. 29-30), Rugosidad (p. 31-32-33-34-35-36-37-38-39), Pie de rey (p. 40-41-42-43-44-45), Palmer (p. 46-47-47-48-49-50-51-52), Proyector de perfiles (p. 53-54-55-56-57-58-59), Comparadores (p. 60-61-62-63-64-65-66), Medidad angulares (p. 67-68-69-70-71-72), Control de radios de cilindros y esferas (73-74-75-76-77-78-79-80), Verificación de engranajes (p. 81-82-83-84-85-86-87-88-89), Verificación de roscas (p. 90-91-92-93-94-95-96-97-98-99), Verificación de máquinas herramientas (p. 100).

Una aproximaci?? al m??tode dimensional Cambrod??

Resumen de la autora en catal??n

Análisis dimensional de las opiniones de los alumnos universitarios sobre sus profesores : comparación entre técnicas paramétricas y no-paramétricas.

Resumen de los autores

Efecto de diferentes agresivos químicos sobre la estabilidad dimensional de diversas resinas termoendurecibles reforzadas.

Se trata de un estudio sobre las alteraciones y sustituciones de los materiales clásicos por materiales de nueva factura. La metodología seguida ha partido de analizar los distintos materiales a través de un estudio de pruebas a los mismos. Finalmente se concluye con la importancia y necesidad de continuar en esta línea de investigación debido a la sustitución paulatina del material aluminio por los materiales plásticos.