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Role based access control (RBAC) has been proved to be effective for defining access control. However, in an environment where collaborative work is needed, additional features should be added on top of RBAC to accommodate the new requirements. In this paper we describe a team access control extension model called TMAC04 (Team-Based Access Control 2004),(More)
We present a new post processing method of simulating depth of field based on accurate calculations of circles of confusion. Compared to previous work, our method derives actual scene depth information directly from the existing depth buffer, requires no specialized rendering passes, and allows easy integration into existing rendering applications. Our(More)
We present a new method for scan-converting a straight line with antialiasing. A scan-converted straight line may contain many pixel segments of identical shapes. Therefore, instead of scanconverting the whole line step by step, we can scan-convert multiple segments of a line through copying and replicating. We discovered that through shifting and copying(More)
Nonlinear projections and implementations are largely unexplored in 3D environments. A technique for generating deformed 3D visual effects using nonlinear perspective projections allows real-time navigation of 3D environments. The authors derive their deformation algorithms from 3D nonlinear perspective projections, which consider factors such as depth,(More)