Designing a visualization framework for multidimensional data

Interest in visualization has grown in recent years, producing rapid advances in the diversity of research and in the scope of proposed techniques. Much of the initial focus in computer-based visualization concentrated on display algorithms, often for specific domains. For example, volume, flow, and terrain visualization techniques have generated significant insights into fundamental graphics and visualization theory, aiding the application experts who use these techniques to advance their own research. More recent work has extended visualization to abstract data sets like network intrusion detection, recommender systems, and database query results. This article describes our initial end-to-end system that starts with data management and continues through assisted visualization design, display, navigation, and user interaction. The purposes of this discussion are to (i) promote a more comprehensive visualization framework; (ii) describe how to apply expertise from human psychophysics, databases, rational logic, and artificial intelligence to visualization; and (iii) illustrate the benefits of a more complete framework using examples from our own experiences.     

The associative processor system CAPRA: architecture andapplications

The basic features of a content-addressable processor/register array (CAPRA) are discussed. The features are the inclusion of logic elements directly within the word cells or bit cells of memory, use of a maskable decoder to enable multiaccess to the memory and computing devices of the array, activity flags within the cells of the array to enable flexible definition of activity patterns, and integration of sensor elements for the direct parallel input of optical data. The architecture's potential applications in database support, basic numerical tasks, and image processing are discussed     

网络安全可视化研究综述

网络安全可视化是近年来网络安全研究的热点。首先说明网络安全可视化的必要性,并给出网络安全可视化的概念、研究步骤及分类,深入分析了多种网络安全可视化方法的优缺点。最后,讨论了该领域当前存在的问题及今后的研究方向。     

Reconfigurable buses with shift switching: concepts andapplications

We propose to enhance traditional broadcast buses by the addition of a new feature that we call shift switching. We show that on a linear array of processors enhanced with shift switching, the prefix sums of n bits can be computed in [log(n+1)/log w] broadcasts, each over n switches, assuming a global bus of width w. Next our prefix sums algorithm is used in conjunction with broadcasting on short buses to obtain several efficient architectural designs for the following fundamental problems: 1) ranking linked lists, 2) counting the number of 1's in a sequence of n bits, and 3) sorting small sets. We see our main contribution in showing that the new bus feature leads to designs that are both theoretically interesting and practically relevant     

Graph visualization techniques for web clustering engines

One of the most challenging issues in mining information from the World Wide Web is the design of systems that present the data to the end user by clustering them into meaningful semantic categories. We show that the analysis of the results of a clustering engine can significantly take advantage of enhanced graph drawing and visualization techniques. We propose a graph-based user interface for Web clustering engines that makes it possible for the user to explore and visualize the different semantic categories and their relationships at the desired level of detail     

Designing fault-tolerant techniques for SRAM-based FPGAs

FPGAs have become prevalent in critical applications in which transient faults can seriously affect the circuit's operation. We present a fault tolerance technique for transient and permanent faults in SRAM-based FPGAs. This technique combines duplication with comparison (DWC) and concurrent error detection (CEO) to provide a highly reliable circuit while maintaining hardware, pin, and power overheads far lower than with classic triple-modular-redundancy techniques.     

Recursive regularization filters: design, properties, andapplications

Least squares approximation problems that are regularized with specified highpass stabilizing kernels are discussed. For each problem, there is a family of discrete regularization filters (R-filters) which allow an efficient determination of the solutions. These operators are stable symmetric lowpass filters with an adjustable scale factor. Two decomposition theorems for the z-transform of such systems are presented. One facilitates the determination of their impulse response, while the other allows an efficient implementation through successive causal and anticausal recursive filtering. A case of special interest is the design of R-filters for the first- and second-order difference operators. These results are extended for two-dimensional signals and, for illustration purposes, are applied to the problem of edge detection. This leads to a very efficient implementation (8 multiplies+10 adds per pixel) of the optimal Canny edge detector based on the use of a separable second-order R-filter     

Correspondence visualization techniques for analyzing andevaluating software measures

One-dimensional statistical methods of scaling have been employed to present a distinct subjective criterion that is related to a measurable aspect of a software component. However, different aspects being measured and different software components being analyzed usually have some characteristics in common. Selected techniques for graphical representation permit a brief but nevertheless thorough view of complex relations among complicated sets of data. Several methods of visualizing and analyzing multidimensional data sets are presented and discussed. The underlying goals of such techniques are to find unknown structures and dependencies among measures, to represent different data sets in order to improve communication and comparability of distinct analyses, and to decrease visual complexity. For improved understandability of the statistical and related graphical concepts, a small set of design aspects from a real-world example is introduced. The techniques illustrated are applied to the same set of data and compared     

A systematic review of software architecture visualization techniques

ContextGiven the increased interest in using visualization techniques (VTs) to help communicate and understand software architecture (SA) of large scale complex systems, several VTs and tools have been reported to represent architectural elements (such as architecture design, architectural patterns, and architectural design decisions). However, there is no attempt to systematically review and classify the VTs and associated tools reported for SA, and how they have been assessed and applied.ObjectiveThis work aimed at systematically reviewing the literature on software architecture visualization to develop a classification of VTs in SA, analyze the level of reported evidence and the use of different VTs for representing SA in different application domains, and identify the gaps for future research in the area.MethodWe used systematic literature review (SLR) method of the evidence-based software engineering (EBSE) for reviewing the literature on VTs for SA. We used both manual and automatic search strategies for searching the relevant papers published between 1 February 1999 and 1 July 2011.ResultsWe selected 53 papers from the initially retrieved 23,056 articles for data extraction, analysis, and synthesis based on pre-defined inclusion and exclusion criteria. The results from the data analysis enabled us to classify the identified VTs into four types based on the usage popularity: graph-based, notation-based, matrix-based, and metaphor-based VTs. The VTs in SA are mostly used for architecture recovery and architectural evolution activities. We have also identified ten purposes of using VTs in SA. Our results also revealed that VTs in SA have been applied to a wide range of application domains, among which “graphics software” and “distributed system” have received the most attention.ConclusionSA visualization has gained significant importance in understanding and evolving software-intensive systems. However, only a few VTs have been employed in industrial practice. This review has enabled us to identify the following areas for further research and improvement: (i) it is necessary to perform more research on applying visualization techniques in architectural analysis, architectural synthesis, architectural implementation, and architecture reuse activities; (ii) it is essential to pay more attention to use more objective evaluation methods (e.g., controlled experiment) for providing more convincing evidence to support the promised benefits of using VTs in SA; (iii) it is important to conduct industrial surveys for investigating how software architecture practitioners actually employ VTs in architecting process and what are the issues that hinder and prevent them from adopting VTs in SA.     

Esoteric theory and techniques

Theory and techniques for reading in the altered state of consciousness (ASC) are presented and illustrated by examples of artistic texts. The concepts of esotericism and reading (fact-finding, cognitive, and creative), as well as perception (conscious (apperception) and subconscious), and the meaning of an artistic work (superficial, explicit, and profound) are refined, ASC examples are given.     

Scientometric analysis of literature on distributed vehicular networks : VOSViewer visualization techniques

Artificial Intelligence Review - The idea of vehicular communication has evolved dramatically over the past two decades apparently with technological advancements that accord low power and memory...     

MaterialVis: Material visualization tool using direct volume and surface rendering techniques

Visualization of the materials is an indispensable part of their structural analysis. We developed a visualization tool for amorphous as well as crystalline structures, called MaterialVis. Unlike the existing tools, MaterialVis represents material structures as a volume and a surface manifold, in addition to plain atomic coordinates. Both amorphous and crystalline structures exhibit topological features as well as various defects. MaterialVis provides a wide range of functionality to visualize such topological structures and crystal defects interactively. Direct volume rendering techniques are used to visualize the volumetric features of materials, such as crystal defects, which are responsible for the distinct fingerprints of a specific sample. In addition, the tool provides surface visualization to extract hidden topological features within the material. Together with the rich set of parameters and options to control the visualization, MaterialVis allows users to visualize various aspects of materials very efficiently as generated by modern analytical techniques such as the Atom Probe Tomography.     

Toward a perceptual theory of flow visualization.

Currently, most researchers in visualization pay very little attention to vision science. The exception is when the effective use of color is the subject. Little research in flow visualization includes a discussion of the related perceptual theory. Nor does it include an evaluation of effectiveness of the display techniques that are generated. This is so, despite Laidlaw's paper showing that such an evaluation is relatively straightforward. Of course, it's not always necessary to relate visualization research to perceptual theory. If the purpose of the research is to increase the efficiency of an algorithm, then the proper test is one of efficiency, not of perceptual validity. But when a new representation of data is the subject of research, addressing how perceptually effective it is - either by means of a straightforward empirical comparison with existing methods or analytically, relating the new mapping to perceptual theory - should be a matter of course. A strong interdisciplinary approach, including the disciplines of perception, design, and computer science will produce better science and better design in that empirically and theoretically validated visual display techniques will result.     

Post-processing and visualization techniques in 2D boundary element analysis

Most post-processors for boundary element (BE) analysis use an auxiliary domain mesh to display domain results, working against the profitable modelling process of a pure boundary discretization. This paper introduces a novel visualization technique which preserves the basic properties of the boundary element methods. The proposed algorithm does not require any domain discretization and is based on the direct and automatic identification of isolines. Another critical aspect of the visualization of domain results in BE analysis is the effort required to evaluate results in interior points. In order to tackle this issue, the present article also provides a comparison between the performance of two different BE formulations (conventional and hybrid). In addition, this paper presents an overview of the most common post-processing and visualization techniques in BE analysis, such as the classical algorithms of scan line and the interpolation over a domain discretization. The results presented herein show that the proposed algorithm offers a very high performance compared with other visualization procedures.     

Interactive clipping techniques for texture-based volume visualization and volume shading

We propose clipping methods that are capable of using complex geometries for volume clipping. The clipping tests exploit per-fragment operations on the graphics hardware to achieve high frame rates. In combination with texture-based volume rendering, these techniques enable the user to interactively select and explore regions of the data set. We present depth-based clipping techniques that analyze the depth structure of the boundary representation of the clip geometry to decide which parts of the volume have to be clipped. In another approach, a voxelized clip object is used to identify the clipped regions. Furthermore, the combination of volume clipping and volume shading is considered. An optical model is introduced to merge aspects of surface-based and volume-based illumination in order to achieve a consistent shading of the clipping surface. It is demonstrated how this model can be efficiently incorporated in the aforementioned clipping techniques.     

Survey of glyph-based visualization techniques for spatial multivariate medical data

In this survey article, we review glyph-based visualization techniques that have been exploited when visualizing spatial multivariate medical data. To classify these techniques, we derive a taxonomy of glyph properties that is based on classification concepts established in information visualization. Considering both the glyph visualization as well as the interaction techniques that are employed to generate or explore the glyph visualization, we are able to classify glyph techniques into two main groups: those supporting pre-attentive and those supporting attentive processing. With respect to this classification, we review glyph-based techniques described in the medical visualization literature. Based on the outcome of the literature review, we propose design guidelines for glyph visualizations in the medical domain.     

Designing communicating transaction processes by supervisory control theory

A Communicating Transaction Process (CTP) is a computational model that serves as a high level specification language for reactive embedded system components and their interactions. It consists of a network of communicating processes coordinating their behaviors via common actions and the common actions are refined as a set of guarded Message Sequence Charts (MSCs). There has been little work devoted to developing CTP models systematically. This paper takes the first step towards bridging this gap. In our work, communicating processes of embedded components are modeled and controlled as Discrete-Event Systems (DES). The control logic among communicating components is derived by Supervisory Control Theory (SCT), so as to guarantee that the communicating processes meet all predefined constraints and possess other desirable system behavioral properties. The control logic is then translated into propositional formulas for guarded MSCs which then results in a CTP model with guaranteed behavioral properties.