Heterogeneous Modeling and Simulation in Ptolemy:

Ptolemy is a modeling tool that is built entirely on Java. one it's main features is allowing heterogeneous modeling. what this means is that it allows to model different system components using different formalisms. this is especially important as it allows for more power in modeling. like for example in embedded systems where each model represent one aspect of the system( some continuous and some are discrete). it certainly limits the modeler if it was only one formalisms she is doing .
Ptolemy's approach is a hierarchically heterogeneous modeling approach, which means that at each level we use the same modeling formalism.

XMULATOR

is a network archeticture simulator, normally netwroks can be indirect or direct (butterfly Vs hypercube ). and could have different switching methods: store & forward, wormhole( where messages are divided into flits that get sent) and there is many potenial bottelnecks. in routing algorithms there is a huge deadlocking concern. that's why simulation of these network archeticture becomes important as for analysis purposes ! Xmulator ( XML + simulator) provides a simulation envirnoment for networks. it's implemented using new and modern(object-oriented) programming languages.(implemented in C#) . it defines topologies using XML. and uses red black trees as data structures. where the first layer is generation of random numbers and data structures. it has many features, like listeners based integration which increases the extensibilty ( listeners are defines the events) . the project will attempt at writing a MT ( model transformation) from atom3 models into an XML file which is the input of the simulator.