Worm plots

Scientists sometimes spend hours conducting experiments only to find that the resulting data proves difficult to analyze with traditional visualization techniques. A typical laboratory experiment, for example, will setup several systems in each of two or more groups-a control group and various treatment groups. The investigator will then measure various parameters for each system over time (sometimes dozens to hundreds of parameters). The investigator tries to answer this question: What is different between the control and treatment groups? Field monitoring of polluted and unpolluted sites within a region result in the same kinds of data and the same difficulties in visualization. Plotting multiple lines on a single 2D plot quickly gets confusing. Plus, the dynamic interactions between parameters can be hard to see. 3D visualizations help researchers make qualitative insights about data more easily. We developed a 3D plotting technique, called “worm plots”, for visualizing these kinds of data. Our visualization tool examines how groups of points change over time. If we plot circles for each time slice, then these circles will change their relative sizes and positions as time goes by. To visualize these evolving dynamics, we connect these time slices with conic sections. This gives us spacetime worms that can be displayed graphically. In our experience, these simple circular cross sections work best when exploring data. They can be rendered quickly and give an easily intuited summary of each group. Further enhancements tend to make the image busy and difficult to interpret     

Discontinuities in continuous scatter plots

The concept of continuous scatterplot (CSP) is a modern visualization technique. The idea is to define a scalar density value based on the map between an n-dimensional spatial domain and an m-dimensional data domain, which describe the CSP space. Usually the data domain is two-dimensional to visually convey the underlying, density coded, data. In this paper we investigate kinds of map-based discontinuities, especially for the practical cases n = m = 2 and n = 3 | m = 2, and we depict relations between them and attributes of the resulting CSP itself. Additionally, we show that discontinuities build critical line structures, and we introduce algorithms to detect them. Further, we introduce a discontinuity-based visualization approach—called contribution map (CM)—which establishes a relationship between the CSP's data domain and the number of connected components in the spatial domain. We show that CMs enhance the CSP-based linking & brushing interaction. Finally, we apply our approaches to a number of synthetic as well as real data sets.     

Faster plots by fan data compression

A fan data compression method is presented that tripled laser printer speed for Bode and simulation plots with many points. This reduced printer delays without the expense of a faster laser printer, and it saved computer time as well. The authors describe their problem, solution, and conclusions. They give the fan algorithm and present its performance for several applications. They include a pseudocode implementation     

Enabling automatic clutter reduction in parallel coordinate plots

We have previously shown that random sampling is an effective clutter reduction technique and that a sampling lens can facilitate focus+context viewing of particular regions. This demands an efficient method of estimating the overlap or occlusion of large numbers of intersecting lines in order to automatically adjust the sampling rate within the lens. This paper proposes several ways for measuring occlusion in parallel coordinate plots. An empirical study into the accuracy and efficiency of the occlusion measures show that a probabilistic approach combined with a 'binning' technique is very fast and yet approaches the accuracy of the more expensive 'true' complete measurement     

基于实时方差时间图法的DDoS攻击检测

分布式拒绝服务攻击(DDoS)是目前最难解决的网络安全问题之一。基于自相似理论求解Hurst参数值存在的问题,在改进的方差时间图算法(OTVTP)的基础上,文章提出了基于自相似参数方差检测DDoS攻击的方法,并设计了采用该方法检测DDoS攻击的模型。实验结果表明,提出的方法能实时、准确检测和区分由DDoS攻击引起的Hurst参数变化,且检测率比传统方法要高。     

Generation and sensitivity of input/output DC plots

A computer program operating in an interactive mode enables input/output DC plots of nonlinear systems to be generated and sensitivity properties to be studied. The computational method is based on the piecewise-linear approach. The technique is applied to simulate transistor curve tracers and to carry out worst-case analysis of transfer characteristics in digital circuits.     

Exploratory data analysis and model criticism with posterior plots

The use of techniques of exploratory data analysis and model criticism represent important stages in many statistical investigations. One of the attractive features of a Bayesian analysis is that it can lend itself well to graphical summary. To produce this graphical summary it is generally necessary to restrict attention to a small number of key parameters. The graphical approach described can be adopted whenever an appropriate likelihood function can be specified. Solutions to some of the principal computational problems associated with implementing a graphical Bayesian analysis based on posterior plots are presented. Nuisance parameters are handled in two ways: by incorporating them directly into the computation of exact posterior distributions; and by integrating them out of a conditional analysis at an early stage when the former approach is infeasible. The latter proposal facilitates the handling of higher dimensional nuisance parameter vectors. Examples taken from the areas of time series and microeconomics are presented to illustrate the efficacy of the approach.     

Absolute stability results for non-linear systems using logarithmic plots

Absolute stability of non-linear systems is examined using the conventional techniques, and a representation of Popov line in the logarithmic gain and phase versus frequency plane. A grapho-analytical procedure is advanced for the Popov line transference to the Bode plane. The technique may be used either as an analytical tool for investigating absolute stability of systems with specified non-linearity sector, or as a synthesis technique for compensator design. The application of the proposed method for substantiating compensator design results is illustrated by two examples.     

Informative PLS score-loading plots for process understanding and monitoring

Principal component regression (PCR) based on principal component analysis (PCA) and partial least squares regression (PLSR) are well known projection methods for analysis of multivariate data. They result in scores and loadings that may be visualized in a score-loading plot (biplot) and used for process monitoring. The difficulty with this is that often more than two principal or PLS components have to be used, resulting in a need to monitor more than one such plot. However, it has recently been shown that for a scalar response variable all PLSR/PCR models can be compressed into equivalent PLSR models with two components only. After a summary of the underlying theory, the present paper shows how such two-component PLS (2PLS) models can be utilized in informative score-loading biplots for process understanding and monitoring. The possible utilization of known projection model monitoring statistics and variable contribution plots is also discussed, and a new method for visualization of contributions directly in the biplot is presented. An industrial data example is included.     

产品设计中的产品识别

产品识别(PI)是产品获得归属感和家族感,企业文化获得认同感的有效设计手段之一。本文对PI概念及其组成要素进行归纳,具体从市场及竞争认知与分析、企业意象、产品意象、产品造型基因四个方面提出PI的构建模式。从产品设计的角度出发,初步探讨产品识别(PI)设计的理论框架。     

A computer program for summarizing scatter plots with robust ellipses

This paper describes a program for summarizing scatter plots with robust ellipses. The program is written in BASIC and is designed for interactive use on a microcomputer graphics terminal to enable quick redesigns of the graph.     

Visualizing flow trajectories using locality-based rendering and warped curve plots

In flow simulations the behavior and properties of particle trajectories often depend on the physical geometry contained in the simulated environment. Understanding the flow in and around the geometry itself is an important part of analyzing the data. Previous work has often utilized focus+context rendering techniques, with an emphasis on showing trajectories while simplifying or illustratively rendering the physical areas. Our research instead emphasizes the local relationship between particle paths and geometry by using a projected multi-field visualization technique. The correlation between a particle path and its surrounding area is calculated on-the-fly and displayed in a non-intrusive manner. In addition, we support visual exploration and comparative analysis through the use of linked information visualization, such as manipulatable curve plots and one-on-one similarity plots. Our technique is demonstrated on particle trajectories from a groundwater simulation and a computer room airflow simulation, where the flow of particles is highly influenced by the dense geometry.     

Matching visual saliency to confidence in plots of uncertain data

Conveying data uncertainty in visualizations is crucial for preventing viewers from drawing conclusions based on untrustworthy data points. This paper proposes a methodology for efficiently generating density plots of uncertain multivariate data sets that draws viewers to preattentively identify values of high certainty while not calling attention to uncertain values. We demonstrate how to augment scatter plots and parallel coordinates plots to incorporate statistically modeled uncertainty and show how to integrate them with existing multivariate analysis techniques, including outlier detection and interactive brushing. Computing high quality density plots can be expensive for large data sets, so we also describe a probabilistic plotting technique that summarizes the data without requiring explicit density plot computation. These techniques have been useful for identifying brain tumors in multivariate magnetic resonance spectroscopy data and we describe how to extend them to visualize ensemble data sets.     

基于产品模型的多级产品配置研究

本文首先对产品配置的通用方法进行了总结,然后对产品配置的相关对象进行了分析,提出了一种产品模型的构造方法,并在此基础上提出了基于产品模型的多级产品配置方法,并给出一个发动机产品配置实例.     

论产品色彩设计与产品色彩感受

产品色彩作为产品设计的第一视觉元素和感受基础,其色彩设计是与形态设计同样重要的前期设计工作。时尚感、科技感、文化感成为产品色彩设计中三个过程的基本感受,这些感受是我们从事产品色彩设计的基本依据。因为人们最基本的色彩本能需求,所以色彩的生理结构、色彩的心理结构、色彩的文化结构,会激励着我们运用这些结构和因素去创造富有时尚感、科技感、文化感的色彩设计的新产品。     

Nyquist plots,finite gain/phase margins & dissipativity

The relation between the small gain theorem and ‘infinite phase margin’ is classical; in this paper we formulate a novel supply rate, called the ‘not-out-of-phase’ supply rate, to first prove that ‘infinite gain margin’ (i.e. non-intersection of the Nyquist plot of a transfer function and the negative half of the real axis) is equivalent to dissipativity with respect to this supply rate. Capturing non-intersection of half-line makes the supply rate system-dependent: a novel feature unobserved in the supply rates considered in the literature so far.