Narrow Results

We present a survey of the hidden surface removal literature, focusing on object-space algorithms. We give a brief definition and history of the problem, followed by a discussion of problems and algorithms associated with the priority ordering of faces. We go on to examine object-space algorithms in order of increasing object complexity: xy-parallel rectangles, ordered triangles, c-oriented faces, c-oriented polyhedra, polyhedral terrains, and general polyhedra. We also review recent work on merging visibility maps and moving viewpoints. Finally, we present a list of open problems.

Concept map has been advocated as an effective tool for teaching, learning, and assessment of conceptual understanding in science education. Although the term “concept map” might not be new to many Chinese mathematics teachers, few of them are familiar with its uses and fewer apply it in educational environments. How Chinese mathematics teachers feel about concept map and how they would use and incorporate it in teaching are issues of interest. This study investigated Chinese mathematics teachers' perceptions of concept map, and their incorporation of concept map in mathematics teaching through lesson plans and practical teaching. With brief introduction, both the prospective and in-service teachers were positive with the use of concept map and indicated a willingness to try it in their classroom teaching. But to actually apply concept map in practice, the teachers, especially the in-service teachers, were to a degree hesitant due to some practical reasons, such as curriculum schedule and pressure from exam. They needed more operational training on concept map to guide their trial and solid evidences to convince them the effectiveness of concept map. Successful initial experience seemed to be a key for teachers' willingness to use concept map in future teaching.