608 research outputs found

    Probabilistic Motion Estimation Based on Temporal Coherence

    Full text link
    We develop a theory for the temporal integration of visual motion motivated by psychophysical experiments. The theory proposes that input data are temporally grouped and used to predict and estimate the motion flows in the image sequence. This temporal grouping can be considered a generalization of the data association techniques used by engineers to study motion sequences. Our temporal-grouping theory is expressed in terms of the Bayesian generalization of standard Kalman filtering. To implement the theory we derive a parallel network which shares some properties of cortical networks. Computer simulations of this network demonstrate that our theory qualitatively accounts for psychophysical experiments on motion occlusion and motion outliers.Comment: 40 pages, 7 figure

    Brave New World. Commentary

    Get PDF

    Deformable Registration through Learning of Context-Specific Metric Aggregation

    Full text link
    We propose a novel weakly supervised discriminative algorithm for learning context specific registration metrics as a linear combination of conventional similarity measures. Conventional metrics have been extensively used over the past two decades and therefore both their strengths and limitations are known. The challenge is to find the optimal relative weighting (or parameters) of different metrics forming the similarity measure of the registration algorithm. Hand-tuning these parameters would result in sub optimal solutions and quickly become infeasible as the number of metrics increases. Furthermore, such hand-crafted combination can only happen at global scale (entire volume) and therefore will not be able to account for the different tissue properties. We propose a learning algorithm for estimating these parameters locally, conditioned to the data semantic classes. The objective function of our formulation is a special case of non-convex function, difference of convex function, which we optimize using the concave convex procedure. As a proof of concept, we show the impact of our approach on three challenging datasets for different anatomical structures and modalities.Comment: Accepted for publication in the 8th International Workshop on Machine Learning in Medical Imaging (MLMI 2017), in conjunction with MICCAI 201

    The Secrets of Salient Object Segmentation

    Get PDF
    In this paper we provide an extensive evaluation of fixation prediction and salient object segmentation algorithms as well as statistics of major datasets. Our analysis identifies serious design flaws of existing salient object benchmarks, called the dataset design bias, by over emphasizing the stereotypical concepts of saliency. The dataset design bias does not only create the discomforting disconnection between fixations and salient object segmentation, but also misleads the algorithm designing. Based on our analysis, we propose a new high quality dataset that offers both fixation and salient object segmentation ground-truth. With fixations and salient object being presented simultaneously, we are able to bridge the gap between fixations and salient objects, and propose a novel method for salient object segmentation. Finally, we report significant benchmark progress on three existing datasets of segmenting salient objectsComment: 15 pages, 8 figures. Conference version was accepted by CVPR 201

    T-cell prolymphocytic leukemia (T-PLL)

    Get PDF
    Review on T-cell prolymphocytic leukemia (T-PLL), with data on clinics, and the genes involved

    The Uses and Gratifications of Dance Reality Television Shows

    Full text link
    The Uses and Gratifications of Dance Reality Shows Competition based dance reality shows are a sub-category under the reality television show genre. One way to add to the growing body of research about reality television shows is to study each sub-category individually in terms of uses and gratifications theory. Therefore this research looked into the reasons why people watch dance reality shows. Since dance is an art form that has deep historic roots, has experienced highs and lows in terms of public perception and has experienced a strong resurgence recently within the realm of reality television, it proves to be an area worthy of investigation. The researcher took a quantitative approach in the quest to support hypotheses that suggested that frequent, moderate and infrequent viewers would have different reasons for viewing, there would be sub-level audiences within the larger overall audience and there would be a relationship between viewing and attitudes toward dance. Surveys were distributed in various classes at the University of Nevada, Las Vegas in attempt to obtain a sample representative of the general UNLV student population. Collected data were run through SPSS Statistical program. Frequencies and principle component factor analysis were used to describe the audience, determine reasons for viewing among frequent, moderate and infrequent viewers and understand their attitudes toward competition based dance reality shows. The results found that frequent, moderate and infrequent viewers do watch for different reasons, there are sub-level audiences within the overall dance reality show viewing audience and that watching dance reality shows doesn\u27t seem to signify an increased interest in dance. Since this research is the first of its kind it can be considered exploratory with the goal of providing guidelines for future researchers

    Application of the theory of bending to the structural members of ships

    Get PDF
    On my return to employment in a shipyard design office after graduating in 1947, I was required to solve many problems of a non-routine nature. These were associated with almost every branch of naval architecture, but structural strength problems predominated and most of the latter were concerned with the local strength of the structural members of ships rather than strength of the hull as a whole. When the opportunity arose for me to carry out research at the University it was not unnatural that I should chose to examine this problem. The main objective was to decide what precautions must be taken when using the theory of elastic bending to analyse the strength of the structural members of ships and to formulate a suitable theory which could be applied in the design offices of shipyards. With the latter end in view it was necessary that the final theory should be as simple as possible and, bearing in mind that in general neither the loads applied to most ship structures nor the strength characteristics of the materials used were accurately known, it was permissible to omit refinements of the theory which would affect the results by less than a few percent. To achieve this object the stresses and deflections measured in the experiments at Glengarnock were compared with those predicted by the theory of bending, and the theory was modified until it could be made to agree with the measurements with reasonable accuracy. This analysis was supplemented by some experimental work on board ship which showed that the theories developed could be applied also in practice. Although the research did not necessarily proceed in a straightforward manner the results are presented in this thesis in a logical sequence. There are five main chapters with a review of the work in a sixth chapter, and an Appendix. Two problems which were peculiar to shipbuilding appeared to be important. The first of these was the difficulty of deciding what degree of constraint there was at the ends of the structural members of ships. To enable this to be taken into account I modified one of the most useful tools of structural analysis - the method of moment distribution. An early version of the theory was sent to the Institution of Naval Architects in an interim report on the research and was published in 1952 (ref. Al), but later revisions were so extensive that a full account of the final theory is given in Chapter I of the thesis. The theory allows for the constraint at the ends of loaded beams which may be straight or curved in the plane of the applied loads and may have constant or variable cross sections. The second problem was that of shear lag in stiffened plating. This occurs in ships and aircraft and had received a good deal of theoretical attention. Many of the theories indicated conflicting results and hardly any experimental work had been published; the G-lengamock results were inconclusive. I therefore investigated the matter by theory and experiment, and the results were published in 1955 by the Institution of Naval Architects. A copy of this paper, together with the discussion, is bound as an Appendix at the end of the thesis and a summary (and one small extension which has a bearing on later work) is given in Chapter II. It is shown that shear lag is usually unimportant in shipbuilding, but a new method of calculating shear lag effects is described for use when required. With this foundation it was found to be possible to commence an analysis of the Glengarnock results and this is discussed in Chapter III. Altogether the results of about 300 experiments were examined. It was found to be possible to correlate a large number of these by means of the theory described in Chapter I, Further modifications or additions to the theory of bending were required in order to account for discrepancies noted in certain classes of specimen, and these are discussed as they arise. An attempt to predict the experimental results entirely from theoretical considerations met with a fair amount of success, A paper on the analysis is nearly ready for submission to the Institution of Naval Architects. In Chapter IV there is a description of some experiments which I carried out on board ship. Measured deflections are compared with those predicted theoretically and, although agreement is not perfect, it is shown that it is possible to estimate fairly accurately the constraint at the ends of a bulkhead stiffener with welded brackets, at any rate in this particular case, by the theory outlined in Chapter I, The theories described are all based on elastic analysis of beams but in Chapter V there is a brief discussion of the possibilities of using the theory of plastic bending in shipbuilding. This is followed in Chapter VI by a review of the research and some conclusions and suggestions for further work

    Motion integration using competitive priors

    Full text link
    Psychophysical experiments show that humans are better at perceiving rotation and expansion than translation [5][9]. These findings are inconsistent with standard models of motion integration which predict best performance for translation. To explain this discrepancy, our theory formulates motion perception at two levels of inference: we first perform model selection between the competing models (e.g. translation, rotation, and expansion) and then estimate the velocity using the selected model. We define novel prior models for smooth rotation and expansion using techniques similar to those in the slow-and-smooth model [23] (e.g. Green functions of differential operators). The theory gives good agreement with the trends observed in four human experiments

    Replicated Bethe Free Energy: A Variational Principle behind Survey Propagation

    Full text link
    A scheme to provide various mean-field-type approximation algorithms is presented by employing the Bethe free energy formalism to a family of replicated systems in conjunction with analytical continuation with respect to the number of replicas. In the scheme, survey propagation (SP), which is an efficient algorithm developed recently for analyzing the microscopic properties of glassy states for a fixed sample of disordered systems, can be reproduced by assuming the simplest replica symmetry on stationary points of the replicated Bethe free energy. Belief propagation and generalized SP can also be offered in the identical framework under assumptions of the highest and broken replica symmetries, respectively.Comment: appeared in Journal of the Physical Society of Japan 74, 2133-2136 (2005
    • …
    corecore