David A. Rabenhorst

Interactive simulation in a multi-person virtual world

A multi-user Virtual World has been implemented combining a flexible-object simulator with a multisensory user interface, including hand motion and gestures, speech input and output, sound output, and 3-D stereoscopic graphics with head-motion parallax. The implementation is based on a distributed client/server architecture with a centralized Dialogue Manager. The simulator is inserted into the Virtual World as a server. A discipline for writing interaction dialogues provides a clear conceptual hierarchy and the encapsulation of state. This hierarchy facilitates the creation of alternative interaction scenarios and shared multiuser environment.

An architecture for virtual worlds

This paper presents a system architecture for creating interactive, multisensory, three-dimensional environments called virtual worlds. The architecture specifically addresses the requirements of virtual worlds for high performance, flexibility, and coordination of concurrent events. Performance is enhanced by a distributed client/server system structure and by efficient overlap of processing time and input/output delay. All processes communicate via asynchronous messages. The functional partitioning of a virtual world requires relatively low bandwidth among the individual processes and the system can be implemented over a conventional local-area network. A key element of this architecture is a central, event-driven dialogue manager that coordinates concurrent input and output events. The dialogue manager provides a clear separation of the interaction techniques from the content of the virtual world as defined by the application. The system is flexible and easily reconfigurable. An interaction technique can be readily changed or replaced because each interaction device is modularized into a separate server and each interaction modality into a separate subdialogue. Subdialogues can be loaded and dropped dynamically, enabling input/output device remapping and the selection of interaction techniques while a virtual world is running. As an initial test of this architecture we have implemented a virtual world for interacting with data from a computational fluid dynamics simulation.

PRIMA: A case study of using information visualization techniques for patient record analysis

We have created an application, called PRIMA (Patient Record intelligent Monitoring and Analysis), which can be used to visualize and understand patient record data. It was developed to better understand a large collection of patient records of bone marrow transplants at Hadassah Hospital in Jerusalem, Israel. It is based on an information visualization toolkit, Opal, which has been developed at the IBM T.J. Watson Research Center. Opal allows intelligent, interactive visualization of a wide variety of different types of data. The PRIMA application is generally applicable to a wide range of patient record data, as the underlying toolkit is flexible with regard to the form of the input data. This application is a good example of the usefulness of information visualization techniques in the bioinformatics domain, as these techniques have been developed specifically to deal with diverse sets of often unfamiliar data. We illustrate several unanticipated findings which resulted from the use of a flexible and interactive information visualization environment.

Towards discovery of event correlation rules

For large installations, event management is critical to ensuring service quality by responding rapidly to exceptional situations. The key to this is having experts encode their knowledge (e.g., in rules, state machines, codebooks) about the relationship between event patterns and actions to take. Unfortunately, doing so is time-consuming and knowledge-intensive. We propose reducing this burden by using offline decision support consisting of visualizing and mining event histories to discover patterns in event data. Our experience with a wide variety of production data has identified several patterns of interest such as, event bursts and partial periodicities. Herein, we use production data to illustrate how to visualize and mine event patterns, and we describe a tool we have developed to aid in pattern discovery.

Interactive exploration of multidimensional data

This paper describes a system called diamond for interactive exploration of multidimensional data. Diamond takes advantage of human pattern recognition and processing capacity, and puts major emphasis on performance and responsiveness. This creates a highly productive symbiosis between the human and the system. The basic philosophy of diamond is to depict the data with pictures, and to help the user manipulate the pictures to rapidly gain insight. Examples of some of the data visualizations the system provides are histograms, 2- and 3- dimensional scatter plots, parametric snake plots, parallel coordinate plots, and novel fractal foam plots. Numerous data presentations can be simultaneously displayed, and easily compared and contrasted. New data visualizations can be dynamically created at any time by making selections among the currently existing ones. The formulation and testing of hypotheses by the human user is expedited by permitting classifications and transformations upon the data from whichever perspective is convenient or interesting.

Complementary visualization and sonification of multidimensional data

Interpretation of multi-dimensional complex data usually involves extracting the relationship between several variables. This is typically done with an interactive visual system . Iugh resolution volumetric data imaging, color, animation, and multiple views are effective tools for data interpretation. Sound can provide an additional and complementary perceptual channel. This presentation focuses on the use of sound with a multi-dimensional imaging system to facilitate the interactive interpretation of complex data. Our methods and system are presented with data from a simulation which computes electron density, hole density, and potential throughout the volume of a three-dimensional semiconductor. The spatial changes and relationships of the three scalar fields are the object of study. Normally the field relations would he examined through multiple visualizations. here, sound is used to augment the visualization by permitting a user to visually concentrate on one field, while listening to the other. Two of the three scalar fields from the simulation arc selected for interpretation and visualized. The 3-dimensional vector gradient of one of them is sonified at a selected focal point within the semiconductor solid. As the current focus i interactively moved through the solid, the representative sound is altered accordingly. The sonification is composed such that local minima and maxima of one of the fields can he found without looking at it.

Visual cues for data mining

This paper describes a set of visual techniques, based on principles of human perception and cognition, which can help users analyze and develop intuitions about tabular data. Collections of tabular data are widely available, including, for example, multivariate time series data, customer satisfaction data, stock market performance data, multivariate profiles of companies and individuals, and scientific measurements. In our approach, we show how visual cues can help users perform a number of data mining tasks, including identifying correlations and interaction effects, finding clusters and understanding the semantics of cluster membership, identifying anomalies and outliers, and discovering multivariate relationships among variables. These cues are derived from psychological studies on perceptual organization, visual search, perceptual scaling, and color perception. These visual techniques are presented as a complement to the statistical and algorithmic methods more commonly associated with these tasks, and provide an interactive interface for the human analyst.

Revitalizing the scatter plot

Computer-assisted interactive visualization has become a valuable tool for discovering the underlying meaning of tabular data, including categorical tabular data. The capabilities of the more traditionally mundane kinds of pictures like scatter plots can be expanded to usefully depict categorical tabular data by incorporating annotations and transforms, and by integrating the extensions into an interactive system.

APL function variants and system labels

While APL extensions are adding power to the language by generalizing and adding operators, the necessity of defining additional attributes of functions is becoming increasingly visible and no longer ignorable. This paper describes the function variant problem, and proposes a solution by introducing the concept of system labels. Three system labels are described: (@@@@)ID for the identity function, (@@@@)INV for the inverse function, (@@@@)FL for the fill function.

APL event / response programming

A proposed mechanism is described by which responses can be programmed to react to APL events. Events can be trapped, and a response is executed either where the trap is laid, or where the event occurs.