16294852
Interactive volume visualization on a heterogeneous message-passing multicomputer
This paper describes VOL2, an interactive general-purpose volume renderer based on ray casting and implemented on Pixel-Planes 5, a distributed-memory, message-passing multicomputer. VOL2 is a pipelined renderer using image-space task parallelism and object-space data partitioning. We describe the parallelization and load balancing techniques used in order to achieve interactive response and near-real-time frame rates. We also present a number of applications for our system and derive some general conclusions about operation of image-order rendering algorithms on message-passing multicomputers.
6332225
Observing a volume rendered fetus within a pregnant patient
Augmented reality systems with see-through headmounted displays have been used primarily for applications that are possible with today's computational capabilities. We explore possibilities for a particular application-in-place, real-time 3D ultrasound visualization-without concern for such limitations. The question is not "How well could we currently visualize the fetus in real time," but "How well could we see the fetus if we had sufficient compute power?" Our video sequence shows a 3D fetus within a pregnant woman's abdomen-the way this would look to a HMD user. Technical problems in making the sequence are discussed. This experience exposed limitations of current augmented reality systems; it may help define the capabilities of future systems needed for applications as demanding as real-time medical visualization.<<ETX>>
30643736
Compound Brushing Explained†
This paper proposes a conceptual model called compound brushing for modeling the brushing techniques used in dynamic data visualization. In this approach, brushing techniques are modeled as higraphs with five types of basic entities: data, selection, device, renderer, and transformation. Using this model, a flexible visual programming tool is designed not only to configure and control various common types of brushing techniques currently used in dynamic data visualization but also to investigate new brushing techniques.
13392863
A Smart Itsy Bitsy Spider for the Web
As part of the ongoing Illinois Digital Library Initiative are expected to worsen as the amount of online informaproject, this research proposes an intelligent agent aption increases. This is mainly due to the problems of proach to Web searching. In this experiment, we develinformation overload and vocabulary differences (Chen, oped two Web personal spiders based on best first 1994; Furnas, Landauer, Gomez, & Dumais, 1987). search and genetic algorithm techniques, respectively. Many researchers consider that devising a scalable apThese personal spiders can dynamically take a user’s selected starting homepages and search for the most proach to Web search is critical to the success of Internet closely related homepages in the Web, based on the and Intranet services, and other current and future Nalinks and keyword indexing. A graphical, dynamic, Javational Information Infrastructure (NII) applications based interface was developed and is available for Web (Chen & Schatz, 1994; Schatz & Chen, 1996). access. A system architecture for implementing such an The main information retrieval mechanisms provided agent-based spider is presented, followed by detailed discussions of benchmark testing and user evaluation by the prevailing Internet WWW-based software are results. In benchmark testing, although the genetic algobased on either keyword search (e.g., Lycos, Alta Vista, rithm spider did not outperform the best first search spiand Yahoo servers) or hypertext browsing (e.g., NCSA der, we found both results to be comparable and comMosaic, Netscape Navigator, and Microsoft Internet Explementary. In user evaluation, the genetic algorithm spiplorer) . Keyword search often results in low precision, der obtained significantly higher recall value than that of the best first search spider. However, their precision poor recall, and slow response time because of the limitavalues were not statistically different. The mutation protions of indexing and communication methods (bandcess introduced in genetic algorithm allows users to find width) , controlled language-based interfaces (the vocabother potential relevant homepages that cannot be exulary problem), and the inability of searchers themselves plored via a conventional local search process. In addition, we found the Java-based interface to be a necesto fully articulate their needs. Furthermore, browsing sary component for design of a truly interactive and dyallows users to explore only a very small portion of the namic Web agent. large Web information space. An extensive information
5225848
Towards an Automated Dental Identification System (ADIS)
This paper addresses the problem of developing an automated system for postmortem identification using dental records. The Automated Dental Identification System (ADIS) can be used by law enforcement agencies to locate missing persons using databases of dental x-rays. Currently, this search and identification process is carried out manually, which makes it very time-consuming and unreliable. In this paper, we propose architecture for ADIS, we define the functionality of its components, and we briefly describe some of the techniques used in realizing these components.
636423
Visualization of large category map for Internet browsing
Information overload is a critical problem in World Wide Web. Category map developed based on Kohonen's self-organizing map (SOM) has been proven to be a promising browsing tool for the Web. The SOM algorithm automatically categorizes a large Internet information space into manageable sub-spaces. It compresses and transforms a complex information space into a two-dimensional graphical representation. Such graphical representation provides a user-friendly interface for users to explore the automatically generated mental model. However, as the amount of information increases, it is expected to increase the size of the category map accordingly in order to accommodate the important concepts in the information space. It results in increasing of visual load of the category map. Large pool of information is packed closely together on a limited size of displaying window, where local details are difficult to be clearly seen. In this paper, we propose the fisheye views and fractal views to support the visualization of category map. Fisheye views are developed based on the distortion approach while fractal views are developed based on the information reduction approach. The purpose of fisheye views are to enlarge the regions of interest and diminish the regions that are further away while maintaining the global structure. On the other hand, fractal views are an approximation mechanism to abstract complex objects and control the amount of information to be displayed. We have developed a prototype system and conducted a user evaluation to investigate the performance of fisheye views and fractal views. The results show that both fisheye views and fractal views significantly increase the effectiveness of visualizing category map. In addition, fractal views are significantly better than fisheye views but the combination of fractal views and fisheye views do not increase the performance compared to each individual technique.
45911957
Hardware accelerated voxelization
Abstract This paper presents a hardware accelerated approach to the voxelization of a wide range of 3D objects, including curves/surfaces, solids, and volumetric CSG models. It allows 3D scenes to be modeled and manipulated in their own representations, and generates the volume representations of regions of interest on-the-fly for volumetric operations. The algorithms take advantages of graphics hardware features in modern graphics workstations, such as texture mapping and frame buffer blending functions, to generate slices of the volume representations for various 3D models. As a result, we are able to perform interactive object manipulations and Boolean operations in an intermixed environment of geometric and volumetric objects under a unified volume graphics framework.
26582047
Optimal intensity control of a multi-class queue
We study a mixed problem of optimal scheduling and input and output control of a single server queue with multi-classes of customers. The model extends the classical optimal scheduling problem by allowing the general point processes as the arrival and departure processes and the control of the arrival and departure intensities. The objective of our scheduling and control problem is to minimize the expected discounted inventory cost over an infinite horizon, and the problem is formulated as an intensity control. We find the well-knowncμ is the optimal solution to our problem.