{"title":"A model of symbol lightness discrimination in sparse scatterplots","authors":"Jing Li, J. V. Wijk, J. Martens","doi":"10.1109/PACIFICVIS.2010.5429604","DOIUrl":"https://doi.org/10.1109/PACIFICVIS.2010.5429604","url":null,"abstract":"Symbols are used in scatterplots to encode data in a way that is appropriate for perception through human visual channels. Color is believed to be the most dominant channel with lightness regarded as the most important one of three color dimensions. We study lightness perception in scatterplots in the context of analytic tasks requiring symbol discrimination. More specifically, we performed an experiment to measure human performance in three visual analytic tasks. Outlined circles and unframed spots, equally sized, with a uniform luminance that was varied at ten or eleven equispaced levels between black and white were used as symbols and displayed on a uniform white background. Sixteen subjects divided in two groups, participated in the experiment and their task performance times were recorded. We propose a model to describe the process. The perception of lightness is assumed to be an early step in the complex cognitive process to mediate discrimination, and psychophysical laws are used to describe this perceptual mapping. Different mapping schemes are compared by regression on the experimental data. The results show that approximate homogeneity of lightness perception exists in our complex tasks and can be closely described by a blended combination of two opposite power functions assuming either the light end or the dark end of the lightness scale as the starting point. The model further yields discriminability scales of lightness for sparse scatterplots with a white background.","PeriodicalId":149295,"journal":{"name":"2010 IEEE Pacific Visualization Symposium (PacificVis)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132827783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Explorable images for visualizing volume data","authors":"Anna Tikhonova, Carlos D. Correa, K. Ma","doi":"10.1109/PACIFICVIS.2010.5429595","DOIUrl":"https://doi.org/10.1109/PACIFICVIS.2010.5429595","url":null,"abstract":"We present a technique which automatically converts a small number of single-view volume rendered images of the same 3D data set into a compact representation of that data set. This representation is a multi-layered image, or an explorable image, which enables interactive exploration of volume data in transfer function space without accessing the original data. We achieve this by automatically extracting layers depicted in composited images. The layers can then be recombined in different ways to simulate opacity changes and recoloring of individual features. Our results demonstrate that explorable images are especially useful when the volume data is too large for interactive exploration, takes too long to render due to the underlying mesh structure or desired shading effect, or if the original volume data is not available. Explorable images can offer real-time image-based interaction as a preview mechanism for remote visualization or visualization of large volume data on low-end hardware, within a mobile device, or a Web browser.","PeriodicalId":149295,"journal":{"name":"2010 IEEE Pacific Visualization Symposium (PacificVis)","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115039089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Graph visualization techniques for conceptual Web site traffic analysis","authors":"W. Didimo, G. Liotta, S. A. Romeo","doi":"10.1109/PACIFICVIS.2010.5429593","DOIUrl":"https://doi.org/10.1109/PACIFICVIS.2010.5429593","url":null,"abstract":"Systems that support Web site traffic analysis are core business intelligence applications for many companies. Recent papers remark that these systems are especially useful if they measure the users' interest into the relevant concepts described in a Web site rather than counting users' accesses to the distinct pages forming theWeb site. This paper extends existing measures of conceptual Web site traffic analysis and describes a system, called COWA, that supports this analysis by means of network models and graph visualization technologies. The graph drawing algorithmic core of the user interface of COWA is a force directed heuristic that computes a simultaneous embedding of two non-planar graphs. This heuristic optimizes the visualizations in terms of crossing resolution and user's geodesic tendency. Experimental results and case studies show the effectiveness of the proposed approach in practice.","PeriodicalId":149295,"journal":{"name":"2010 IEEE Pacific Visualization Symposium (PacificVis)","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128272418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Nakao, K. W. Hung, S. Yano, Koji Yoshimura, K. Minato
{"title":"Adaptive proxy geometry for direct volume manipulation","authors":"M. Nakao, K. W. Hung, S. Yano, Koji Yoshimura, K. Minato","doi":"10.1109/PACIFICVIS.2010.5429597","DOIUrl":"https://doi.org/10.1109/PACIFICVIS.2010.5429597","url":null,"abstract":"This paper introduces a new design to allow interactive, direct manipulation of volume data on volumetrically rendered images. We present an adaptive volume proxy mesh which serves not to define surfaces, but to encode the geometry and physical state of the volume. This system performs a modeling-free form of direct volume deformation by adaptively constructing the whole geometric structure on the background while keeping the structure transparent to the user. A complex, high-frequency structure is locally encoded into the mesh on-the-fly based on the user's volume of interest. This paper also presents a scheme for volume shading/shadowing applied in combination with our framework for improving reality in the visualization of time-varying deformable objects. We demonstrate examples of geometry-encoded direct volume manipulation and application to volume exploration and surgical simulation.","PeriodicalId":149295,"journal":{"name":"2010 IEEE Pacific Visualization Symposium (PacificVis)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124018335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Interactive volumetric lighting simulating scattering and shadowing","authors":"Timo Ropinski, Christian Döring, C. Rezk-Salama","doi":"10.1109/PACIFICVIS.2010.5429594","DOIUrl":"https://doi.org/10.1109/PACIFICVIS.2010.5429594","url":null,"abstract":"In this paper we present a volumetric lighting model, which simulates scattering as well as shadowing in order to generate high quality volume renderings. By approximating light transport in inhomogeneous participating media, we are able to come up with an efficient GPU implementation, in order to achieve the desired effects at interactive frame rates. Moreover, in many cases the frame rates are even higher as those achieved with conventional gradient-based shading. To evaluate the impact of the proposed illumination model on the spatial comprehension of volumetric objects, we have conducted a user study, in which the participants had to perform depth perception tasks. The results of this study show, that depth perception is significantly improved when comparing our illumination model to conventional gradient-based volume shading. Additionally, since our volumetric illumination model is not based on gradient calculation, it is also less sensitive to noise and therefore also applicable to imaging modalities incorporating a higher degree of noise, as for instance magnet resonance tomography or 3D ultrasound.","PeriodicalId":149295,"journal":{"name":"2010 IEEE Pacific Visualization Symposium (PacificVis)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114647043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fanny Chevalier, Stéphane Huot, Jean-Daniel Fekete
{"title":"WikipediaViz: Conveying article quality for casual Wikipedia readers","authors":"Fanny Chevalier, Stéphane Huot, Jean-Daniel Fekete","doi":"10.1109/PACIFICVIS.2010.5429611","DOIUrl":"https://doi.org/10.1109/PACIFICVIS.2010.5429611","url":null,"abstract":"As Wikipedia has become one of the most used knowledge bases worldwide, the problem of the trustworthiness of the information it disseminates becomes central. With WikipediaViz, we introduce five visual indicators integrated to the Wikipedia layout that can keep casual Wikipedia readers aware of important metainformation about the articles they read. The design of WikipediaViz was inspired by two participatory design sessions with expert Wikipedia writers and sociologists who explained the clues they used to quickly assess the trustworthiness of articles. According to these results, we propose five metrics for Maturity and Quality assessment of Wikipedia articles and their accompanying visualizations to provide the readers with important clues about the editing process at a glance. We also report and discuss about the results of the user studies we conducted. Two preliminary pilot studies show that all our subjects trust Wikipedia articles almost blindly. With the third study, we show that WikipediaViz significantly reduces the time required to assess the quality of articles while maintaining a good accuracy.","PeriodicalId":149295,"journal":{"name":"2010 IEEE Pacific Visualization Symposium (PacificVis)","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126987731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}