Abstract CORDIC (Coordinate Rotation Digital Computer) is an iterative algorithm for the calculation of a two-dimensional vector in circular, linear or hyperbolic coordinate systems. This paper presents a survey of known CORDIC algorithms and architectures for the rotation and vectoring mode in the circular cordinate system. In addition an implementation of the differential CORDIC algorithm in VHDL has been done. The implementation is designed to keep the fast timing and throughput characteristic known for on-line redundant arithmetic..

AimThe purpose of the study was to investigate how upper secondary school students experience performance demands during their physical education and health classes (PE-classes). The questions were as following: Are there differing perceptions between the sexes whether students experience performance demands? In what situations do the students feel that the demands on their performance are high during PE-classes? Do the students experience of demands on performance differ whether the physical education and health teacher is male or female? Do students feel unfairly treated by the physical education and health teacher during PE-classes?MethodSeven upper secondary schools in Stockholm?s administrative district were randomly selected to participate in the survey. The principals were contacted for further information and to set a date for performing the survey. The project leaders were present during the days the surveys were taken by students in the social science and natural science programs.