1. INTRODUCTION. The classical theorem of Ptolemy (used for computations by Claudius Ptolemaeus of Alexandria, 2nd century AD, but probably known even before him [7, pp. 123-1241) states that if A, B , C , D are, in this order, four points

The Ptolemy project studies modeling, simulation, and design of concurrent, real-time, embedded systems. The focus is on assembly of concurrent components. The key underlying principle in the project is the use of well-defined models of computation that govern the interaction between components.

| A hardware software cosimulation environment is developed using the backplane approach. This paper de nes the backplane protocol for communication and synchronization between client simulators to seamlessly integrate a new simulator without modi cation. Automatic interface generation facility is also devised for more e ective cosimulation environment. The environment is implemented based on P...

physical explanation of the planets’ place in the heaven is one of the principal questions in the ancient astronomy which the authors of hay?a (cosmology) works tried to find an answer for it. their opinion is in fact a compilation from aristotle’s “fifth element” theory and ptolemy’s “prisms” theory. aristotle’s fifth element theory assumes that the substance of the heavens is different from t...