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TitleModel Transformation with Hierarchical Discrete- Event Control
TagsUniversity Of California
File Size1.4 MB
Total Pages139
Table of Contents
                            List of Figures
	Syntax of Actor Models
	Specification of Transformation Rules
	Transformation Engine
	Event-Oriented Control Language
Basic Transformation
	Visual Syntax
	Graph Representation of Actor Models
	Graph, Morphism and Transformation
	Criteria and Operations
	Model Transformation Based on Graph Transformation
		Alternative Visual Syntax
		Selective Tags
		Higher-Order Specification in a Declarative Language
	Requirement for Efficient Control
Ptolemy Event Relationship Actors
	Flat Models
		Introductory Examples
		Canceling Relations
		Simultaneous Events
		Model Execution Algorithm
		Example: Car Wash Simulation
	Hierarchical Models
		An Abstract Framework for Model Execution
		Ptera Semantics in the Abstract Framework
		Semantic Equivalence for Flat Models
		Hierarchical Car Wash Model
	Composition with Heterogeneous Models of Computation
		Composition with DE
		Composition with FSMs
		Hierarchical Heterogeneous Model Design
Model-Based Transformation
	The Constant Optimization Example
	Programming Interface for Events
	An Event Library for Model Transformation
		The Model Variable
		Match and Transform Events
		Auxiliary Events
		Transformation Test between Ptera and DDF
		Identity Test between Ptera, DDF and C generated from DDF
	Model Optimization
	Configurable Product Families
Document Text Contents
Page 1

Model Transformation with Hierarchical Discrete-
Event Control

Thomas Huining Feng

Electrical Engineering and Computer Sciences
University of California at Berkeley

Technical Report No. UCB/EECS-2009-77

May 20, 2009

Page 69

Java Printing


first parameter the model that issues the request and as the second parameter a model

time when firing of that model should occur. That model time should be equal to

or greater than the current model time. For example, when Postfire is invoked with

model M contained in M ′, fireAt may be issued with parameters M and t. The

director of M ′ receives that request and schedules to fire M when the model time

reaches t.

3.2.2 Ptera Semantics in the Abstract Framework

Compared to the execution algorithm for flat Ptera models in 3.1.5, an alternative

way to define the semantics is by defining all the methods in the abstract framework.

This alternative way yields an equivalent semantics for flat models, but it additionally

supports hierarchical models.

In the following discussion, M denotes a Ptera model. M ′ is the model that

contains M in the model hierarchy, if it exists. m represents a submodel contained

in M , if any.

The event queue of M is denoted by Q. It is a priority queue that stores scheduled

events and fireAt requests from the submodels. Events are sorted in the order dis-

cussed previously. fireAt requests are sorted by their time stamps. If a fireAt request

and an event have the same time stamp, then the fireAt request is sorted before the

event. If two fireAt requests have the same time stamp, they are sorted with the

LIFO or FIFO policy, depending on when those fireAt requests were received.

Page 70


An additional initializing attribute is defined for each scheduling relation. It takes

a Boolean value that determines whether the submodel of the scheduled event, if there

is any, should be initialized every time that event is processed. If the attribute is false,

the submodel would be initialized only if it has not been initialized or its postfire has

returned false last time (meaning that its previous execution has finished).

An additional variable S denotes a set of references to the submodels of M that

have been initialized.

◦ Preinitialize M :

Initialize Q and S to be empty

For each event e in M in the ≤e order

If e is associated with a submodel m

Preinitialize m

◦ Initialize M :

For each initial event e in M in the ≤e order

Create an instance ie and append it to Q

Set the time stamp of ie to be the current model time

If container M ′ exists and Q is not empty

Issue fireAt to M ′ with the current model time

◦ Prefire M returns Boolean:

If Q is not empty

Page 138


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