18,448 research outputs found
Finding Outliers in Surface Data and Video
Surface, image and video data can be considered as functional data with a
bivariate domain. To detect outlying surfaces or images, a new method is
proposed based on the mean and the variability of the degree of outlyingness at
each grid point. A rule is constructed to flag the outliers in the resulting
functional outlier map. Heatmaps of their outlyingness indicate the regions
which are most deviating from the regular surfaces. The method is applied to
fluorescence excitation-emission spectra after fitting a PARAFAC model, to MRI
image data which are augmented with their gradients, and to video surveillance
data
Multiple Uncertainties in Time-Variant Cosmological Particle Data
Though the mediums for visualization are limited, the potential dimensions of a dataset are not. In many areas of scientific study, understanding the correlations between those dimensions and their uncertainties is pivotal to mining useful information from a dataset. Obtaining this insight can necessitate visualizing the many relationships among temporal, spatial, and other dimensionalities of data and its uncertainties. We utilize multiple views for interactive dataset exploration and selection of important features, and we apply those techniques to the unique challenges of cosmological particle datasets. We show how interactivity and incorporation of multiple visualization techniques help overcome the problem of limited visualization dimensions and allow many types of uncertainty to be seen in correlation with other variables
Visualization of Categorical Response Models - from Data Glyphs to Parameter Glyphs
The multinomial logit model is the most widely used model for nominal multi-category responses. One problem with the model is that many parameters are involved, another that interpretation of parameters is much harder than for linear models because the model is non-linear. Both problems
can profit from graphical representations. We propose to visualize the effect strengths by star plots, where one star collects all the parameters connected to one explanatory variable. In contrast to conventional
star plots, which are used to represent data, the plots represent parameters and are considered as parameter glyphs. The set of stars for a fitted model makes the main features of the effects of explanatory variables on
the response variable easily accessible. The method is extended to ordinal models and illustrated by several data sets
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