Motion Recovery by Integrating over the Joint Image Manifold

Recovery of epipolar geometry is a fundamental problem in computer vision. The introduction of the “joint image manifold” (JIM) allows to treat the recovery of camera motion and epipolar geometry as the problem of fitting a manifold to the data measured in a stereo pair. The manifold has a singularity and boundary, therefore special care must be taken when fitting it. Four fitting methods are discussed—direct, algebraic, geometric, and the integrated maximum likelihood (IML) based method. The first three methods are the exact analogues of three common methods for recovering epipolar geometry. The more recently introduced IML method seeks the manifold which has the highest “support,” in the sense that the largest measure of its points are close to the data. While computationally more intensive than the other methods, its results are better in some scenarios. Both simulations and experiments suggest that the advantages of IML manifold fitting carry over to the task of recovering epipolar geometry, especially when the extent of the data and/or the motion are small.     

Mixed mode failure criteria for brittle elastic V-notched structures

Three mixed mode failure initiation criteria at reentrant corners in brittle elastic materials are examined. Prediction of failure load and crack initiation angle are compared to experimental observations carried out on PMMA (polymer) and MACOR (glass ceramic) V-notched specimens. Since the mode mixity ratio influences greatly both the failure load and crack initiation angle, a detailed experimental procedure has been followed, focusing on obtaining a wide range of mode mixity ratios. It is demonstrated that by assuming a sharp V-notch tip some failure criteria predict reasonably well both the crack initiation angle and failure load.     

Graininess of judgment under uncertainty: An accuracy-informativeness trade-off.

This work concerns judgmental estimation of quantities under uncertainty. The authors suggest that the "graininess" or precision of uncertain judgments involves a trade-off between 2 competing objectives: accuracy and informativeness. Coarse (imprecise) judgments are less informative than finely grained judgments; however, they are likely to be more accurate. This trade-off was examined in 3 studies in which participants ranked judgmental estimates in order of preference. The patterns of preference ranking for judgments support an additive trade-off model of accuracy and informativeness. The authors suggest that this trade-off also characterizes other types of uncertain judgments, such as prediction, categorization, and diagnosis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A violation of pure insertion: Mental rotation and choice reaction time.

Six experiments tested the assumption that the mental rotation process is purely inserted into a mirror–normal discrimination task. In Exp 1, Ss took significantly longer to respond to upright characters in blocks containing rotated stimuli than in blocks containing only upright stimuli. Exps 2 and 3 showed that this rotational uncertainty effect was not caused by the need to determine stimulus orientation, and Exp 4 showed that it was independent of the visual quality of the stimulus. Exp 5 showed that the effect was greatly reduced when Ss performed a go–no-go task rather than choice reaction time (RT), and Exp 6 showed that it was independent of the complexity of the response required in the choice task. Results suggest that response selection in a choice RT mirror–normal discrimination task is altered when mental rotation is added, violating the assumption of pure insertion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inhibitory effect of Aspergillus niger on the growth of Aspergillus ochraceus and Aspergillus flavus,and on aflatoxin formation

Aspergillus ochraceus and A flavus were grown on synthetic media (SM) supplemented with 50 or 200 ml litre^?1 SM on which A niger had been grown previously ( ‘A niger medium’ = ANM). Controls included SM acidified to pH 6.0 or 4.4, SM diluted with 50 or 200 ml litre^?1 water, and diluted-acidified SM. For both fungi, higher growth inhibition was recorded on ANM-containing SM than in the controls. Aflatoxin formation was markedly inhibited on SM to which 20 ml litre^?1 ANM extract (in methanol/chloroform, 2:1 v) had been added, although the growth of A flavus on that medium was almost the same as that in the control. It is concluded that the inhibitory effect of A niger on the growth of fungi should not be attributed merely to pH reduction, but also, mainly, to metabolites produced by the fungus in the growth medium, even at early stages of its growth.     

Crossover of Marital Dissatisfaction During Military Downsizing Among Russian Army Officers and Their Spouses.

This study examined mechanisms of strain crossover within couples and the moderating role of gender. Data were collected at a time of military downsizing from a sample of 1,250 Russian army officers and their spouses. The authors tested a model that incorporated 3 mechanisms for the crossover of marital dissatisfaction among dual-earner couples. The model provided support for 2 suggested crossover mechanisms: direct reactions of crossover and indirect mediated effects through social undermining. Strong evidence was also provided for gender asymmetry in the crossover process. Marital dissatisfaction crossed over from husbands to wives but not vice versa, and social undermining behavior played a role in the process of crossover of marital dissatisfaction for husbands but not for wives. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Image-based animation of facial expressions

We present a novel technique for creating realistic facial animations given a small number of real images and a few parameters for the in-between images. This scheme can also be used for reconstructing facial movies where the parameters can be automatically extracted from the images. The in-between images are produced without ever generating a three-dimensional model of the face. Since facial motion due to expressions are not well defined mathematically our approach is based on utilizing image patterns in facial motion. These patterns were revealed by an empirical study which analyzed and compared image motion patterns in facial expressions. The major contribution of this work is showing how parameterized “ideal” motion templates can generate facial movies for different people and different expressions, where the parameters are extracted automatically from the image sequence. To test the quality of the algorithm, image sequences (one of which was taken from a TV news broadcast) were reconstructed, yielding movies hardly distinguishable from the originals. Published online: 2 October 2002 Correspondence to: A. Tal Work has been supported in part by the Israeli Ministry of Industry and Trade, The MOST Consortium     

Explaining counterexamples using causality

When a model does not satisfy a given specification, a counterexample is produced by the model checker to demonstrate the failure. A user must then examine the counterexample trace, in order to visually identify the failure that it demonstrates. If the trace is long, or the specification is complex, finding the failure in the trace becomes a non-trivial task. In this paper, we address the problem of analyzing a counterexample trace and highlighting the failure that it demonstrates. Using the notion of causality introduced by Halpern and Pearl, we formally define a set of causes for the failure of the specification on the given counterexample trace. These causes are marked as red dots and presented to the user as a visual explanation of the failure. We study the complexity of computing the exact set of causes, and provide a polynomial-time algorithm that approximates it. We then analyze the output of the algorithm and compare it to the one expected by the definition. The algorithm is implemented as a feature in the IBM formal verification platform RuleBase PE, where the visual explanations are an integral part of every counterexample trace. Our approach is independent of the tool that produced the counterexample, and can be applied as a light-weight external layer to any model checking tool, or used to explain simulation traces.     

Tomographic reconstruction of incompressible flow

In many experiments facilitating tomography the reconstruction problem is under-determined, meaning there are many possible solutions consistent with the measurements. If the sampling rate is fast relative to the typical evolution time, the known physical dynamics of the system can be used as additional reconstruction constraints. Here we demonstrate that incorporating the requirement of incompressible flow can improve significantly the fidelity of the reconstructed sequence. The incompressibility of the reconstruction is assured by requiring the conservation of the density moments. It is demonstrated that the "incompressible" reconstruction can be significantly more accurate than the reconstruction using standard methods. A consequence of the density moments' conservation is the conservation of the density histogram throughout the reconstructed sequence.