This paper describes the design and development of a VR system that can assist orthopedic diagnosis and surgery. A realistic 3D knee surface model, integrated with motion analysis, is used to visualize the geometrical and biomechanical characteristics of human knee joint. The system can be used to perform pre-operative surgery simulation and evaluation in a VR environment.

Ivfost current architectureshave registers organized in one of two ways: single register sets; or register stacks,

An evaluation stack, used exclusively to store temporary values in expression evaluation, is known to be an effective mechanism in the implementation of high level languages. This work considers the efficient management of evaluation stacks for concurrent programming languages. Techniques for sharing a single evaluation stack among many processes, without copying on process switches, are developed. The best strategy for managing the evaluation stack is shown to depend strongly upon the scheduling paradigm adopted by the run-time support of the language. Simulation studies, driven by synthetic workloads, show that the techniques described in this paper exhibit substantial performance improvements over traditional temporary storage management schemes for concurrent languages.