T he Ptolemy Project (http:/ www.ptolemy.ca) is a recently developed model of electronic access to medical literature for surgeons in developing countries. The program provides for East African surgeons to become research affi liates of the University of Toronto and have access to the full text resources of the university library, via a secure system that monitors and evaluates their usage [1]....

The mapping class group of a surface with one boundary component admits numerous interesting representations including as a group of automorphisms of a free group and as a group of symplectic transformations. Insofar as the mapping class group can be identified with the fundamental group of Riemann’s moduli space, it is furthermore identified with a subgroup of the fundamental path groupoid upo...

Typical complex systems that involve microsensors and microactuators exhibit heterogeneity both at the implementation level and the problem level. This naturally leads to a heterogeneous approach to system design that uses domain-specific models of computation (MoC) at various levels of abstractions to define a system, and leverages multiple CAD tools to do simulation, verification, and synthes...

1. Chronological remarks. The main source for our knowledge of ancient astronomy is Ptolemy. His Mathematical composition, commonly known as the Almagest, quotes observations of his own ranging from 127 to 142 A.D. [35; 36; 37]. This work seems to be the earliest of a whole series of fundamental works, such as his Geography [41 ], the Tetrabiblos [39; 40], and so on, whose influence on mediaeva...

Ptolemy II is a powerful software package that models heterogeneous systems. Its infrastructure offers the ability to create distributed models, but lacks the security mechanisms to protect data being transferred in these models. The lack of security can lead to many potential threats and breaches of information. Potential attackers can jeopardize system stability by manipulating data in transi...

This paper describes the use of Ptolemy to automatically generate code for heterogeneous multiprocessor systems. The framework presented lets the designer migrate from simulation to code generation while developing an application that is specified by constructing a dataflow graph. From primitive send and receive actors, the framework can automatically construct three classes of interprocessor c...

This paper proposes an approach to implement Metropolis quantity manager mechanism in Ptolemy II, by utilizing the AspectJ which adds to Java aspect-oriented programming (AOP) capabilities. The benefits and limitations of this approach are also discussed.

In this paper we study geodesic Ptolemy metric spaces X which allow proper and cocompact isometric actions of crystallographic or, more generally, virtual polycyclic groups. We show that X is equivariantly rough isometric to a Euclidean space.