Globe4D is an interactive four-dimensional globe. It is a projection of the Earth's surface on a physical sphere. The sphere can be freely rotated along all axes, viewed from any angle and enables the user to control time as its fourth dimension. An application was created that shows the historical movement of the continents, known as continental drift. Besides the Earth, any planet or spherical object can be projected. This paper describes the background, aims, results and progress of this student project.

Systems of heterogeneous parallel processing are studied such as arising in parallel programs executed on distributed systems. A lower and an upper bound model are suggested to obtain secure lower and upper bounds on the performance of these systems. The bounding models are solved by using a matrix-geometric algorithmic approach. Formal proofs of the bounds are provided along with error bounds on the accuracy of the bounds. These error bounds in turn are reduced to simple computational expressions. Numerical results are included. The results are of interest for application to arbitrary fork-join models with parallel heterogeneous processors and synchronization.

A discrete-time extension is obtained of recent product form results for random access schemes. A proof technique is presented that is new in that the global balance equations, which are much more complicated than the continuous-time analogs, are verified by inductively proving a multiple partial balance notion. An illustration of present-day applications is given. Particularly, randomized protocols are included and explicit discrete-time product form analogs of continuous-time results are obtained with applications in (1) carrier-sense multiple-access (CSMA) protocols such as busy tone multiple access (BTMA) and rude-CSMA, (2) circuit switching structures, and (3) metropolitan area network (MAN) systems.>