At the IST and SPIE 96 conference, the author reported a successful cooperative visualization case study that involved using an internet web-browser for data dissemination and data visualization applications between the US and Japanese offices. This cooperative visualization effort using computers and the web-browser has been evaluated, and it has pointed the way to the current research involving the use of the World Wide Web environment for real-time simulation and interactive visualization. Since the spring of 1996, the author has been using Fujitsu's new multi-processor supercomputer VPP300 for fast numerical model simulations and data generations. Meanwhile, the web technology has been advancing very quickly, and it now provides many tools and methods for the scientific visualization. In the summer of 1996, the author began to work on a prototype for a real-time supercomputing interactive visualization system based on the available World Wide Web browser tools and a Fujitsu visualization software known as VisLink. The intranet version of this system was completed in December of 1997. Design issues and a case study of the prototype will be discussed in this paper.

The amount and variety of data on the Web continues to grow exponentially, greatly complicating the process of finding relevant information, and making it increasingly difficult to understand information in the context of related material. Advanced visualization techniques, as long as they are compatible and effective ion the context of the widely distributed nature of data on the Web, can provide some measure of order to this chaos. Despite the proliferation of automated tools which attempt to deal with this sea of data, there is still a pressing need for human involvement in the organization and representation of information. People 'living' on the Web tend to form little 'knowledge spaces', revolving around those subjects that they are interested in. We describe several research efforts currently underway which address the problem of organizing and finding information in Cyberspace. We conclude with 'CiteMaps', a technology we are developing which combines Web-relevant visualization techniques with concepts and tools, to allow 'real people' to develop shareable clusters of related information.

Based on the hypothesis of a one-to-one relationship between the external symptoms of epileptic fits and the abnormal cerebral functioning which causes it, the computerized study of epileptic fit video tapes brings new information on abnormal neuron activity. This insight will improve specialist's analysis in their diagnoses.

Accurate measurement of the strain fields developed in the human ventricular system in the brain would require invasive monitoring at a number of selected spatial locations. Since this is not practically possible the gross behavior of a field must be deduced from time-gated MRI scanned images. The phase-encoded images taken at several coronal locations from posterior to anterior, yield a field averaged over many cardiac cycles. A second sequence of time-gated MRI images are recorded in the same fashion to obtain the range of pulsatile movement of the membrane boundary of the cortical surface. The two data sets provide spatial and temporal information that must be combined in such a way that the flow field complies with the movement of the boundary. Modeling this behavior requires a combination of finite element and hydrostatic models. The finite element model of the ventricles consists of a triangulated surface mesh boundary that has a time varying pressure field applied uniformly to its surface to reflect the continuous change in pressure from systole to diastole and the observed deformation of the brain surface. The interior tetrahedra have displacements applied, posterior to anterior, that reflect the displacements from the phase-encoded sequences.

Software written in the Java programming language is platform independent, remotely executable and downloadable on demand. In this paper, we describe a toolkit developed in Java for the purpose of visualizing and analyzing biomedical images. It is comprised of a number of class libraries that enable selection, viewing, manipulation and analysis of biomedical images. Java's class libraries and special features such as interfaces, multithreading, etc., are extensively used in the design and implementation of the toolkit. The current version of the visualization toolkit supports viewing of JPEG and GIF images only. A medical image viewer developed using this toolkit can be used by doctors in hospitals, offices or at any other locations using a Java-enabled web browser running on a variety of hardware/software platforms.

We introduce concepts and construction of a system for the generation of diagram editors based on object-oriented model informations. Only the object-oriented model and the definition of the desired diagram notation has to be provided by the software developer. The software developer specifies symbols to be used as a graphical representation for the instances of a class and defines graphical link constellations to represent links between these instances. The system allows the automated integration of an object- oriented database management system for the management of diagram and application information.

Weather forecasts are typically produced once or twice each day. Each run usually covers several forecast periods. Over the course of the day, as measured sensor data becomes available, discrepancies between observation s and model forecasts are resolved and integrated so as to update and improve the next forecast run. The process of resolving the differences between model output and sensor measurements is known as data assimilation. Traditional methods include kriging and optimal interpolation. They involve statistical and historical information on reliability of sensor measurements, variability of the field, model resolution, initial and boundary conditions, etc. Some of the parameters of a data assimilation model are integration techniques, choice and frequency of incremental update methods, interpolation algorithms, resolution of the model grid, estimation filtering and smoothing algorithms and finite differencing schemes. All of these parameters can have a profound effect on the tendencies displayed by a forecasting model Hence, having visualization tools to display these possibly conflicting information is very useful for the scientists in quickly identifying regions of high conflict and/or regions of low confidence levels. Allowing the scientists to control the data assimilation variables can assist in constructing a protocol that is appropriate for a specific geographical region. This paper presents a suite of visualization tools to aid scientists in performing their data assimilation analyses. These tools will provide an integrated display of 3D model outputs with 0D point measurements from meteorological stations, 1D measurements from wind profilers, sonde, and floating buoys, 2D measurements from CODAR current measurements and GOES satellite feed, and, when available, 3D volume measurements from NEXRAD data. The tools provided here will help extend the 2D domain in which data assimilation is currently being performed to include analysis of the overall method as well as visualizations of the separate weather measurements.

Uncertainty or errors are introduced in scientific visualization as the data is acquired, transformed and rendered. In this work, we focus on the uncertainty introduced by the interpolation process. Appropriate tools for investigating the geometry of these interpolants are crucial in determining the accuracy of these interpolants or comparing and contrasting these interpolants. A visualization tool for investigating this geometric uncertainty of surface interpolants was recently reported by Lodha et al. This tool combines various traditional techniques such as side-by-side viewing, differencing, pseudo-coloring with more modern techniques such as glyphs, transparency and texture. One of the limitations of this software was that it could be used to compare only tow surfaces at a time. This was rather inconvenient if one were to compare two surface interpolants at the same time with a given 'true' surface. MUSURF fills this gap by allowing users to visually compare two surface interpolants together with the 'true' surface. This simplifies the task of comparative evaluation of two interpolants considerably. MUSURF also extends the software in several directions. First, it adds a few more capabilities to the geometric uncertainty system. The two most important capabilities are cross-sectional contours and correlating the errors with glyphs. Finally, MUSURF incorporates sound capabilities to distinguish between several surface interpolants at the same time. We also present applications of MUSURF to analytic and digital elevation data sets.

In this paper we present a system for visualizing volume data from remote supercomputers. We have developed both parallel volume rendering algorithms, and the World Wide Web (WWW) software for accessing the data at the remote sites. The implementation uses Hypertext Markup Language, Java, and Common Gateway Interface scripts to connect WWW servers/clients to our volume renderers. The front ends are interactive Java classes for specification of view, shading , and classification inputs. We present performance results, and implementation details for connections to our computing resources at the University of California Santa Cruz including a MasPar MP-2, SGI Reality Engine-RE2, and SGI Challenge machines. We apply the system to the task of visualizing trabecular bone from finite element simulations. Fast volume rendering on remote compute servers through a web interface allows us to increase the accessibility of the results to more users. User interface issues, overview of parallel algorithm developments, and overall system interfaces and protocols are presented. Access is available through Uniform Resource Locator http://www.cse.ucsc.edu/research/slvg/.

In distributed computing environment, an important factor affecting performance of parallel algorithm is communication bandwidth. A new parallel volume rendering algorithm is presented in this paper, based on Shear-Wrap factorization of the viewing transformation using pipeline framework of PCs. Taking full use of overlap of communication and computing, we overcome the bottleneck of communication. In the existing algorithms based on object partition, local rendering and image composition are divided into two serial processes. Communication hardly happens during local rendering. In the period of image compositing, however, communication is very busy, and even congested. Furthermore, there are a big synchronism overhead in this period. This paper well solves this drawback by making local rendering and image compositing concurrently through pipeline of PCs. We have experimented on a pipeline composing of 16 Pentiums. The results shows that, performance is not affected much by communication and system overhead is little compared to rendering time. This paper provides a new method for studying on low-price, high-efficiency and real-time volume rendering system.

Symmetric multiprocessor systems (SMPs) are the desktop systems of the future. As they become more widely used, application developers will need to make better use of them. Merely providing threading will be insufficient. Companies will need to provide applications that parallelize portions of code and use the processors in SMPs to their full extent. This will have a much more dramatic effect on improving performance. Before this can be achieved however, tools must be developed which aid programmers, who may have little or no experience in programming parallel systems, to debug and performance tune their applications. Our goal is to improve the technology available through interactive computational steering and to develop techniques that will be valuable for all types of concurrent systems not just SMPs. This will be done through integrated operation visualization, data highlighting, interactive computational steering, and by concentrating on the data in a parallel system rather than on the processors or code.

With the availability of ever increasing numbers of documents from the Internet and other sources, finding what you are looking for is becoming increasingly difficult. This paper presents a new approach to finding documents that relies on compelling and useful graphic presentations to the user. Exploiting techniques first used in the field of Scientific Visualization, this approach is an example of work in the growing field of Information Visualization. By creating compact representations of documents that can be transferred over the Internet, the approach allows the search process to occur on the users desktop, distant from where the original documents are stored or where the indexes are created. Besides allowing searching to scale better to large numbers of information consumers, this allows the full graphical capabilities of the desktop computer to be applied to the problem The ability to search for specific user keywords is replaced by user selection of topics from a list created by expert topic designers. The approach complements keyword searching as a way of finding information.

We describe an artistic project that uses scientific tools to convey a sense of place. Detail is an important element in creating an artistic sense of place. This detail must be consistent with what we know about the correlation between topography and its surface appearance. The vegetation and exposed rock in the mountains of the North Slope of the Brooks Range are distinctly correlated with the digital terrain. Analysis of elevation, slope, and aspect generates tools used to create a probability mapping between the terrain and the appearance of the surface. Digital painting techniques create texture maps that we wrap around 3D models of the terrain. We use these models in our animation of a traverse of the landscape. These techniques aid in the development of high resolution geometry. A persistent theme in this process is the use of visual metaphor and visual thinking. Active geomorphology and the viscous flow of vegetation characterize the northeastern mountains of the Brooks Range. The vegetation exists, not so much in competition, but in response to solar energy niches. Colony ecology is significant. The surface creeps in response to the flow of water and ice. The ecology and topography appear unmodified by human hands. One gets the impression that the forces of nature are consistently and clearly expressed. Our art uses science to create a representation of this dynamic landscape.

This paper presents a technique to losslessly compress and progressively transmit floating point data using wavelets. MPI is employed in the implementation of this technique so that the parallelized solver which runs on a remote computer and the visualization tool which runs on a local graphics workstation can be combined.

In this paper, we describe an implementation method that enables users to real time control their avatars that is real and complex shaped in a 3D virtual world. We realized an avatar using quasi 3D models and moving picture, enabling movement and actions to be performed in real time according to user operations. This avatar has the following characteristics. 1) The avatar is highly precise. 2) Avatar actions can be controlled in real time. 3) The avatar has smooth actions. We also describe an evaluation of our implementation method. A prototype system consisting of avatars capable of performing walking action using a quasi 3D model comprised of five polygons and a virtual 3D shared space containing these avatars was created, and the effectiveness of this system was confirmed.

Understanding and subsequently fine-tuning concurrent object-oriented programs may be difficult. To alleviate this situation, program visualization can be used. This research focuses on the question of what and how such visualization can be done for concurrent object-oriented systems. Furthermore, in the absence of language support, to what extent such visualization can be realized. To investigate these issues, Visor++, a tool for visualizing CC++ programs, is developed. This research proposes that both static and dynamic views of programs are important. However, many languages, including CC++, do not provide adequate support for program visualization. CC++, in particular, provides rudimentary support which is available only in the low-level run-time system. Therefore, proper support must be facilitated by Visor++. To make such support portable and maintainable, it is provided at the CC++ source-code level. Although some information, such as changes in variable and data structure values, cannot be easily captured by such an approach, experiments with Visor++ have shown that the information obtained can be of valuable assistance for understanding and fine-tuning programs.

When making an animation by moving inside a 3D scene, areas close to the camera will be larger on the screen and the limited resolution of the data will become visible. To make more natural appearing scene it is necessary to enhance the resolution of these areas. An initial version is made from the lower resolution data by interpolation and then individual pixels are adjusted to make it better match a desired texture. The texture is derived from a number of closeup photographs by a classification algorithm which compares the local low resolution data with low resolution versions of the closeups. Rather than choosing a single closeup as a target texture, the classification algorithm generates a similarity score between thee region to be enhanced and each of the closeup samples. This score is then sued as a weighting function to determine how closeups may be used directly by comparing them to the enhanced region as it is being corrected, or for increased efficiency, they may be measured for some parameters and then the enhanced region is made to match these parameters.

The line integral convolution (LIC) method, which blurs white noise textures along a vector field, is an effective way to visualize overall flow patterns in a 2D domain. The method produces a flow texture image based on the input velocity field defined in the domain. Because of the nature of the algorithm, the texture image tends to be blurry. This sometimes makes it difficult to identify boundaries where flow separation and re-attachments occur. We present techniques to enhance LIC texture images and use colored texture images to highlight flow separation and re- attachment boundaries. Our techniques have been applied to several flow fields defined in 3D curvilinear multi-block grids and scientists have found the results to be very useful.

A novel layered visualization model is proposed to provide a systematic approach for visualizing and manipulating information with complex structure. A heterogeneous multiple level composite container type concept is introduced to model any arbitrary complex data structure. The necessary visualization and manipulation strategies are also provided within the model. Based on the model, an efficient application-independent visualization engine has been designed and implemented. A type wrapper concept is used to provide a general application interface. Applications can easily interact with the visualization engine by registering application-dependent type wrappers into the engine. THE engine has been sued as the graphical interface to a distributed object-oriented multimedia database management system.

This paper reports the results of a project to develop an interactive visualization artifact to view data from a utility market as a natural scene. The visualization was the product of a series of experiments and prototypes, with the final design bearing structural resemblance to a decorated tree. It presents the raw data and its patterns of change within an integrated structure consisting of color-coded graphs, layers of pie charts, iconic markers, and parallel coordinates, while retaining overall comprehensibility. This paper details process based on the methodology or Robertson, a prototype implementation illustrated with an example walk through, and we comment on the merit of this approach.

We have developed a software framework that simplifies the task of implementing, controlling, and visualizing space- variant image filters. A filter's behavior over an image is dictated by the parameters that control it. The values of each parameters can be data, geometric, algorithmic, or user dependent. We call this the parameter's source-dependence. Parameters can also vary over any number of image dimensions. We call this the parameter's dimensionality- dependence. Using the parameter dependence classification scheme as a base, the software framework provides tools that allow visualization of filter properties, and where appropriate, interactive user control. A median filter is a simple example of a data dependent filter. We make explicit the components of data analysis and filtering, and use it to show how filter properties can be visualized. A space- variant band-pass filter, used in seismic data processing, shows how user interaction can be incorporated into the framework. Finally, a simple geometric warp shows how geometric dependent filters benefit.

This paper describes an approach for a platform- and implementation-independent design of user interfaces using the UIMS idea. It is a result of a detailed examination of object-oriented techniques for program specification and implementation. This analysis leads to a description of the requirements for man-machine interaction from the software- developers point of view. On the other hand, the final user of the whole system has a different view of this system. He needs metaphors of his own world to fulfill his tasks. It's the job of the user interface designer to bring these views together. The approach, described in this paper, helps bringing both kinds of developers together, using a well defined interface with minimal communication overhead.

In this approach, two basic services designed for the engineering of computer based systems are combined: a symbol-oriented man-machine-service and a high speed database-service. The man-machine service is used to build graphical user interfaces (GUIs) for the database service; these interfaces are stored using the database service. The idea is to create a GUI-builder and a GUI-manager for the database service based upon the man-machine service using the concept of symbols. With user-definable and predefined symbols, database contents can be visualized and manipulated in a very flexible and intuitive way. Using the GUI-builder and GUI-manager, a user can build and operate its own graphical user interface for a given database according to its needs without writing a single line of code.

This paper presents a structure and set of tools to address the needs of groups of scientists working on large, time- dependent simulations. It describes a direct manipulation, 3D steering environment that is integrated with a controller for instrumenting parallel computations, collecting output, and passing it in binary mode between heterogeneous machines. The instrumentation allows collection of data at chosen points in the model and control of the computation through changes of parameters of insertion of alternate data. The steering interface and controller are joined with a library of collaborative communication tools. With these tools a user may steer a simulation and share visualization tools within the group. In addition a time-dependent steering interface has been introduced. Here time is treated on exactly the same basis as the spatial dimensions so there is a 4D environment, 3 shown spatially and one through animation. The steering interface is built upon a flexible visualization/analysis system. This permits the immediate display of time-dependent results from the dynamic simulations and refined interaction with the results to bring out the character and correlations of multivariate data. The user can then launch new simulations at any stage in this exploration using the visualization to define and focus the simulation parameters, region of interest, and time frame.

Based on our experience in the design and construction of interactive resource reallocation systems, we argue about the advisability of interactive visualization as a means to increase the effectiveness of an intelligent system and we present a generic framework for solving rescheduling problems. A presentation of a flight rescheduling systems we have built, serves as the main implementation example of our proposed paradigm. We explain the specific visualization methods employed in the system and how visualization, coupled with artificial intelligence techniques, can aid in the difficult task of resource allocation.

This paper describes an approach for the interactive creation and configuration of plant monitors and controls. It is based on top of three basic services, which were built to solve several often found problems: Fluids for general man machine interaction, IAM, an intelligent measurement and control service and a platform independent real-time operating system for distributed applications. The described solution combines these services to allow an interactive configuration management and the execution of the resulting model.

We present a conceptual model for interaction in exploratory data visualization systems. This model extends interaction to systems that use geometry, texture, color, and sound to present data to the user. Such systems need to be highly interactive and user centered. We extend interaction to utilize not only geometry, but also color and sound representations of data. Our conceptual model supports interaction in multiple representational spaces. A representational space is a space, such as a color space or a sound space, that is used in the representation of data. The model extends the conventional visualization output pipeline, separating the data from its representations. Interaction operations can be performed on either part of the pipeline.

The main focus of this contribution is the description of mechanisms for an intuitive input of user-data with a direct response to gain fast parameter selection. To build polymorph i input methods for different parameters classes, a database containing knowledge about each operator is needed. This information about the syntactical and semantical structure is used to create adequate dialog elements, like sliders, list boxes, text fields, etc., each one responsible for a distinct parameter class. In addition higher-level semantics are used to aggregate data types, e.g., the user can draw a rectangle interactively, instead of only inputting the coordinates of its corners. Depending on the context, the user can also change certain subsets of the knowledge about the operator to fit special needs. Incremental computation of the results of an operator by successively expanding regions of interest is used to gain direct feedback for every change of parameter values. So by dragging a slider for the size of a smoothing mask, e.g., the user can see the effect directly and thus select the desired value rapidly. This approach is extended to sequences of operators. In this case, more than one parameters form will be open at the same time, one for each relevant operator, to have full control of all important values.

We present an interactive software tool for manipulating image data, especially high resolution multi-spectral solar movies and images from several different instruments. This tool contains procedures for distortion removal for ground based solar movies, correlation tracking, image alignments, data compression, 3D FOurier filtering, interactive viewing of space/time slices in movies, and browsing through data cubes. This is a compete public domain package based on X windows and Unix which is currently running on Silicon Graphics and Digital Equipment workstations. These software tools are freely available to the international solar community. Many components are also applicable to image an movie analysis in astrophysics, space physics, and earth sciences. They are available with documentation via our web pages under http://www.space.lockheed.com.

DataSpace is a multi-platform software system for easily visualizing relational databases using a set of flexible 3D graphics tools. Typically, five attributes are selected for a given visualization session where two of the attributes are used to generate 2D plots and the other three attributes are used to position the 2D plots in a regular 3D lattice. Mouse-based 3D navigation with constraints allows the user to see the 'forest and the trees' without getting 'lost in space'. DataSpace uses the Standard Query Language to allow connection popular database systems. DataSpace also incorporates a variety of additional tools e.g., aggregation, data 'drill down', multidimensional scaling, variable transparency, query by example, and display of graphics from external applications. Labeling of node contents is automatic. 3D strokefonts are used to provide readable yet scalable text in a 3D environment. Since interactive 3D navigation is essential to DataSpace, we have incorporated several methods for adaptively reducing graphical detail without losing information when the host machine is overloaded. DataSpace has been sued to visualized databases containing over 1 million records with interactive performance. In particular, large databases containing stock price information and telecommunications customer profiles have been analyzed using DataSpace.

Many applications demand the capability of retrieval based on image content. A classification mechanism is needed to categorize images based on feature similarity. An effective classification of the images can support efficient retrieval of images. In this paper, we investigate a feature-based approach to image clustering and retrieval. Four different texture-based feature sets of images are extracted using Haar and Daubechies wavelet transforms. Using multi- resolution property of wavelets, we extract the features at different levels. The experimental results of our clustering approach on air photo images are reported.