The feasibility of motion and structure from noisy time-varying image velocity information

This research addresses the problem of noise sensitivity inherent in motion and structure algorithms. The motion and structure paradigm is a two-step process. First, we measure image velocities and, perhaps, their spatial and temporal derivatives, are obtained from time-varying image intensity data and second, we use these data to compute the motion of a moving monocular observer in a stationary environment under perspective projection, relative to a single 3-D planar surface. The first contribution of this article is an algorithm that uses time-varying image velocity information to compute the observer's translation and rotation and the normalized surface gradient of the 3-D planar surface. The use of time-varying image velocity information is an important tool in obtaining a more robust motion and structure calculation. The second contribution of this article is an extensive error analysis of the motion and structure problem. Any motion and structure algorithm that uses image velocity information as its input should exhibit error sensitivity behavior compatible with the results reported here. We perform an average and worst case error analysis for four types of image velocity information: full and normal image velocities and full and normal sets of image velocity and its derivatives. (These derivatives are simply the coefficients of a truncated Taylor series expansion about some point in space and time.) The main issues we address here are: just how sensitive is a motion and structure computation in the presence of noisy input, or alternately, how accurate must our image velocity information be, how much and what type of input data is needed, and under what circumstances is motion and structure feasible? That is, when can we be sure that a motion and structure computation will produce usable results? We base our answers on a numerical error analysis we conduct for a large number of motions.     

Validity of alternative self-report indices of smoking among adolescents.

The convergent validity of popularly used open-ended and closed-ended self-report measures of smoking was examined. Carbon monoxide (CO) samples were obtained from 11th-grade Canadian students as an independent method of assessing recent smoking. In addition to CO, 5 known psychosocial correlates of smoking (attitude, subjective norm, risk taking, best friend's smoking, and other friends' smoking) were used to estimate convergence with the self-report smoking indices. Results indicate that both simple closed-ended scales, with only a few response options, and more continuous, open-ended measures performed about equally as well as correlates of CO and the psychosocial measures, but only if the open-ended scales were subjected to a normalizing transformation to optimize their convergence. After this transformation was performed, convergence depended more on the time-span covered by the self-report indices than on the open-ended/closed-ended distinction. Implications of these results for different assessment goals were discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

驱动中型LED背光系统的集成方案

在LED的背光应用上。LED相对于CCFL有更多的优点。但以往的背光驱动器并不能完全发挥出先进LED技术的潜能。现今美国国家半导体的LM3431驱动器凭着卓越的性能和灵活性，使这一完美的背光驱动器将LED技术的潜能发挥至极限。     

Projection pursuit classification of multiband polarimetric SARland images

Results are presented for an experiment utilizing a pastoral land scene with a variety of eight classes, imaged by the NRL dual band (X and L) polarimetric synthetic aperture radar (NUWSAR) at a spatial resolution of 1.2 m. Projection pursuit (PP) statistical analysis tools were applied to a set of simultaneous L-band and X-band fully polarized images (six independent channels) to demonstrate the utility of land classification at high spatial resolution from a light aircraft using SAR. The statistical confusion matrix was used as a quantitative optimization measure of classification. Samples of eight classes from a portion of the scene were used to define a training set, then PP tools were used for classification. It is clear that L-band and X-band fully polarized data view the classes in a significantly different manner, and each brings independent information to the analysis. These results are not meant to be exhaustive at this time but to demonstrate the utility of applying PP tools to multiband and polarization SAR data and to give an indication of the quality of classification one can achieve with moderately high spatial resolution SAR data using a light plane platform     

Alarm reaction in acquisition and social transmission of simulated-predator recognition by zebra danio fish (Brachydanio rerio).

Alarm reactions occur in response to alarm substance passively released by injury to skin of zebra danio fish (Brachydanio rerio). Visual observation of alarmed conspecifics yields socially facilitated alarm by observers. Concurrent exposure of fish to alarm substance and a novel odorant (morpholine) later produced learned alarm to morpholine alone. Fish trained with morpholine plus alarm substance were mixed in with naive fish for a test with morpholine alone. The naive fish, separated out from the mixed groups, then demonstrated not only an acquired alarm reaction to morpholine but also an ability to communicate the acquired recognition of a simulated predator to a new group of naive observers. The results suggest the operation of a sophisticated antipredator defensive system in zebra danios that involves unlearned releasing stimuli, social facilitation, visual communication, learned predator recognition, and social communication of predator recognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

MMPI differences between alcoholics and drug abusers: Effect of age and race.

Inpatients in Veterans Administration substance-abuse treatment programs voluntarily took the Minnesota Multiphasic Personality Inventory (MMPI) as part of a routine clinical evaluation. The alcohol-dependence-only group (n?=?207) were older (M?=?49.6 years) and had a higher percentage of White Ss (72.9%) than did either the drug-dependence group (n?=?49, M?=?32.9 years, Whites?=?53.1%) or a mixed alcohol- and drug-dependence group (n?=?160, M?=?35.0 years, Whites?=?60.0%). Previously reported differences between alcoholics and drug abusers in depression and psychopathy were obtained when age and race were not used as covariates, but no differences were found when the effects of age and race were statistically controlled. Mixed alcohol and drug abusers had somewhat more pathological MMPI scores than did alcoholics, even when effects due to age and race were partialed out. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Two-Fluid Hydrodynamics in Trapped Bose Gases and in Superfluid Helium

A review is given of recent theoretical work on the superfluid dynamics of trapped Bose gases at finite temperatures, where there is a significant fraction of non-condensate atoms. One can now reach large enough densities and collision cross-sections needed to probe the collective modes in the collision-dominated hydrodynamic region where the gas exhibits characteristic superfluid behavior involving the relative motions of the condensate and non-condensate components. The precise analogue of the Landau-Khalatnikov two-fluid hydrodynamic equations was recently derived from trapped Bose gases, starting from a generalized Gross-Pitaevskii equation for the condensate macroscopic wavefunction and a kinetic equation for the non-condensate atoms.     

US national lab fights viruses

Sandia National Laboratories already lists the fastest computer in the world (ASCI Red) and the fastest home-assembled computer in the world (C-Plant) among its credentials. Now, the people at Sandia’s US Department of Energy National Security Laboratory are turning their attention toward another arena: developing an intelligent software agent capable of defending against network hackers and computer viruses.     

Holographic polymer dispersed liquid crystals (HPDLCs) containing triallyl isocyanurate monomer

The morphology and corresponding performance of holographic polymer dispersed liquid crystals (HPDLCs) based on thiol-ene polymer are dependent on a number of factors including the gel point conversion of the polymer, polymerization kinetics, and extent of liquid crystal (LC) phase separation. Previous research of HPDLC reflection gratings made from thiol-allyl ether polymer indicates that increasing polymerization rate in systems with moderate gel point conversion can improve diffraction efficiency (DE). This work examines HPDLC reflection gratings that contain the ene monomer triallyl isocyanurate (TATATO). In HPDLCs, thiol-TATATO polymerization is two times faster than the thiol-ene polymerization of triallyl ether. By substituting TATATO for triallyl ether, the LC droplet size within HPDLC reflection gratings decreases from 100 nm to 25 nm. The dramatic reduction in LC droplet size for thiol-TATATO HPDLCs increases baseline transmission from 55% in thiol-triallyl ether HPDLCs to 90% at 450 nm. Unfortunately, the DE of thiol-TATATO HPDLCs is only approximately 10% due to poorly defined lamellae in the grating morphology. As determined with real-time IR (RTIR) spectroscopy, thiol-TATATO HPDLCs have significantly faster LC demixing kinetics in comparison to thiol-allyl ether HPDLCs. During holographic photopolymerization, the increased rate of LC demixing causes formation of LC droplets throughout the grating. The low DE of thiol-TATATO HPDLCs can be improved by mixing TATATO and allyl ether monomer. The morphology of ternary thiol-ene HPDLC formulations containing TATATO and allyl ether has a well-defined grating structure due to increased LC solubility in the system, an average LC droplet size of 50 nm, and baseline transmission of nearly 85% at 450 nm.