Visualizing the implicit information of trajectory data is very important for analyzing human activities and is of great value in the decision making process. The objective of our research is to provide a semantic visualization method for trajectory data and the result of analysis. To format the trajectory data, we propose an object-oriented abstract data type (ADT). An event, which represents ...

1. A few years ago Rogers [1] showed that, if K is any convex body in n-dimensional Euclidian space, there is a covering of the whole space by translates of K with density less than nlogn+nloglogn+5n, provided n > 3. However the fact that the covering density is reasonably small does not imply that the maximum multiplicity is also small. In the natural covering of space by closed cubes, the den...

Rubik’s Revenge, a 4× 4× 4 variant of the Rubik’s puzzles, remains to date as an unsolved puzzle. That is to say, we do not have a method or successful categorization to optimally solve every one of its approximately 7.401×10 possible configurations. Rubik’s Cube, Rubik’s Revenge’s predecessor (3×3×3), with its approximately 4.33 × 10 possible configurations, has only recently been completely s...

This study evaluates the spatial-temporal patterns in Virginia tornadoes using National Weather Service Storm Prediction Center’s Severe GIS (SVRGIS) database. In addition to descriptive statistics, analysis employs Kernel Density Estimation for spatial pattern and space-time cubes visualize spatiotemporal frequency of potential trends. Most 726 between 1960–2019 occurred Eastern Virginia, alon...

The elegant notion of a space with walls was introduced by Haglund and Paulin [6]. Prototypical examples of spaces with walls are CAT(0) cube complexes, introduced by Gromov in [5]. The purpose of this note is to observe that every space with walls has a canonical embedding in a CAT(0) cube complex and, consequently, a group action on a space with walls extends naturally to a group action on a ...

The remote sensing of hydrologic variables such as rainfall, soil moisture and streamflow is becoming increasingly more important as we strive to improve our understanding of the earth’s climate. Because these variables change more rapidly than other land cover characteristics, a high frequency of image acquisition is required. This in turn results in a large volume of data that must be compare...

We demonstrate a system of tools for real-time detection of significant clusters of spatial events and observing their evolution. The tools include an incremental stream clustering algorithm, interactive techniques for controlling its operation, a dynamic map display showing the current situation, and displays for investigating the cluster evolution (time line and space-time cube).