Archive for January, 2008
Segmentation-Based Retrieval of Document Images from Diverse Collections
We describe a methodology for retrieving document images from large extremely diverse collections. First we perform content extraction, that is the location and measurement of regions containing handwriting, machine-printed text, photographs, blank space, etc, in documents represented as bilevel, greylevel, or color images. Recent experiments have shown that even modest per-pixel content classication accuracies can support usefully high recall and precision rates (of, e.g., 8090%) for retrieval queries within document collections seeking pages that contain a fraction of a certain type of content. When the distribution of content and error rates are uniform across the entire collection, it is possible to derive IR measures from classication measures and vice versa. Our largest experiments to date, consisting of 80 training images totaling over 416 million pixels, are presented to illustrate these conclusions. This data set is more representative than previous experiments, containing a more balanced distribution of content types. Contained in this data set are also images of text obtained from handheld digital cameras and the success of existing methods (with no modication) in classifying these images with are discussed. Initial experiments in discriminating line art from the four classes mentioned above are also described. We also discuss methodological issues that aect both ground-truthing and evaluation measures.
Polymer MEMS System for Measuring the Mechanical Modulus of a Biological Cell
The measurements of the mechanical modulus of biological cells are critical to studies of pathophysiology and the research for an effective treatment. This research has developed a rapid and cost effective technique in order to measure the Poissons ratio and mechanical modulus of a live biological cell by utilizing microelectromechanical system (MEMS) techniques in a biological application. The design, fabrication, and characterization of a polymer-based MEMS system that integrates a V-shaped electrothermal actuator array and a cell-positioning system in a single microelectronics chip are presented here. This BioMEMS device compressed a NIH3T3 fibroblasts cell and caused up to 25% mechanical strain.
Grain Growth Kinetics in Co-doped Aluminas: ReIation with Grain Boundary Complexions
It is being gradually recognized that there are various types of dopant/impurity segregation induced grain boundary complexions in polycrystalline oxides; starting from an ordered segregation of dopants, going through a series of changes in decreasing crystalline order and finally forming an intergranular glassy film. It is also understood that the formation and stability of these boundary complexions are functions of thermodynamic variables like dopant concentration, grain boundary energy and temperature etc. In a series of grain growth kinetics experiments in our laboratory, ultrahigh purity polycrystalline alumina doped with controlled amounts of Ca, Si, Nd, Y, La etc. has shown discontinuities in the grain boundary mobility that could be linked to the various types of grain boundary complexions observed. In alumina co-doped with Y and Si, the boundary mobility increases by orders of magnitude as compared to alumina doped with Y alone. The present work aims to discuss the outcomes of detailed boundary mobility measurements in alumina co-doped with Cu-Ti, Zr-Si and Y-Si under similar conditions over a wide temperature range and relate the boundary mobility values to various grain boundary complexions.
TT Hydrae: UV Analysis of an Algol Binary
TT Hydrae (HD 97528) is an Algol-type interacting binary star system composed of a B9.5 V primary star and a K0 III-IV companion in a 6.95 day orbit. The companion fills its Roche Lobe and material is streaming into an accretion cloud around the primary. Ultraviolet spectra from FUSE, IUE, HST-FOS, and HST-GHRS taken over about twenty years are being analyzed to create a model of the gas flow in the system. The spectra are composed of ten emission spectra taken during totality of primary eclipse and eighteen absorption spectra from outside of primary eclipse totality.
Ultraviolet Spectroscopy of R Arae: An Active Interacting Binary Star
The eclipsing, interacting binary star system R Arae (HD149730) is in a very active and very rare stage of its evolution. After receiving some attention in the 1980s and early 1990s, R Ara has unfortunately been neglected. A total of 124 high resolution ultraviolet spectra (taken by the IUE satellite) are analyzed. The data taken in September of 1989 are especially of interest considering that there are 36 consecutive spectra that span the entire 4.4-day orbital period. R Ara is believed to consist of a B9 primary and an unknown (early F to K ?) secondary, and is engulfed in a thick, nebulous plasma resulting from rapid mass flow within and from the system. Several light curves spanning the UV region were generated. In addition to continuum flux levels and radial velocities, the results of photometric and spectroscopic analyses are presented. These studies reveal clues about the construction of this interacting binary (mass flow direction, high temperature regions, etc.) and help to identify its evolutionary status. There is a peculiar but consistent apparent eclipse past phase 0.5, as well as another consistent minimum at around first quadrature. Non-orbital gas motions are observed, with Mg II and Si IV exhibiting clear gas stream effects. R Ara is most likely at the end of its first phase of rapid mass transfer, on its way to becoming a classic Algol-type system.