PowerPointPrsentation

1
Declarative Modeling
Modeling and Simulation of Computer Systems
Institute of Parallel and Distributed Systems,
University of Stuttgart
Author
Christian Hiesinger
Supervisor
Olga Saukh
February 21, 2005
1/22
2
Declarative Modeling
Overview
Introduction

• Definition of modeling

• Application areas

• Types of modeling

Declarative Modeling

• General information

• State-Based Approach

• Event-Based Approach

• Hybrid State-Event Methods

Conclusion
2/22
3
Declarative Modeling
Introduction
Definition of modeling
Replication of reality
Application areas
Computer science, space travel, architecture, etc.
Types of modeling

• Declarative Modeling

• Conceptual Modeling

• Functional Modeling

• Constraint Modeling

• Spatial Modeling

3/22
4
Declarative Modeling
Declarative Modeling
General Information
State-Based Approach

• Deterministic Automata

• Nondeterministic Automata

• Production Systems

Event-Based Approach

• Finite Event Automata

• Keyframe Animation

• Augmented Event Graphs

Hybrid State-Event Methods

• State-Event Graphs

• Petri Networks

4/22
5
Declarative Modeling
General Information
What is it?

• Notions of states and events

• State change

When is it used?

• Time divided into discrete parts

• Space divided into discrete parts

Where is it used?

• Computer science

• Computer graphics

• Production processes

• ...

5/22
6
Declarative Modeling
Declarative Modeling
General Information
State-Based Approach

• Deterministic Automata

• Nondeterministic Automata

• Production Systems

Event-Based Approach

• Finite Event Automata

• Keyframe Animation

• Augmented Event Graphs

Hybrid State-Event Methods

• State-Event Graphs

• Petri Networks

6/22
7
Declarative Modeling
State-Based Approach
Deterministic Automata
Properties

• State change on input

• Only one possibility to react on input

Features

• Easiely understandable models

• Clearly arranged models

Usage

• Regular automata

• UML

7/22
8
Declarative Modeling
State-Based Approach
Deterministic Automata
Example
Start transaction
Waiting
Transmitting
Start calculation
Wait
Start transaction
Calculating
Transmitting
Finite state machine of a server process
8/22
9
Declarative Modeling
State-Based Approach
Nondeterministic Automata
Properties

• Extension of deterministic automata

• Transitions are labeled with probability values

• Possibility of time tags

Features

• Nondeterminism

Usage

• Scheduling jobs

• Bioinformatics

• Computerlinguistics

9/22
10
Declarative Modeling
State-Based Approach
Nondeterministic Automata
Example
0,8
0,3
0,5
0,5
0,3
0,2
0,7
0,6
0,1
Markov model of a bug scrabbling trough waypoints
10/22
11
Declarative Modeling
Declarative Modeling
General Information
State-Based Approach

• Deterministic Automata

• Nondeterministic Automata

• Production Systems

Event-Based Approach

• Finite Event Automata

• Keyframe Animation

• Augmented Event Graphs

Hybrid State-Event Methods

• State-Event Graphs

• Petri Networks

11/22
12
Declarative Modeling
Event-Based Approach
Finite Event Automata
Properties

• Resembles finite state automata

• Transitions are labeled with time tags

Features

• Easy understandable models

• Clearly arranged models

Usage

• Same areas as finite state automata

12/22
13
Declarative Modeling
Event-Based Approach
Finite Event Automata
Example
5
Start transaction
Start calculation
25
500
5
Start transaction
Transmission finished
13/22
14
Declarative Modeling
Event-Based Approach
Keyframe Animation
Properties

• Models the boundaries of a system

• Models look like film stripes

Features

• Motions can be modeled ostensible

Usage

• Computer graphics

14/22
15
Declarative Modeling
Event-Based Approach
Keyframe Animation
Example
Keyframe animation of a simple screensaver
15/22
16
Declarative Modeling
Declarative Modeling
General Information
State-Based Approach

• Deterministic Automata

• Nondeterministic Automata

• Production Systems

Event-Based Approach

• Finite Event Automata

• Keyframe Animation

• Augmented Event Graphs

Hybrid State-Event Methods

• State-Event Graphs

• Petri Networks

16/22
17
Declarative Modeling
Hybrid State-Event Methods
State-Event Graphs
Properties

• Can be described through message sequence charts

• Several processes are modeled

Features

• Ostensible modeling of interaction

Usage

• Distributed systems

• Physics (Space-time diagrams)

17/22
18
Declarative Modeling
Hybrid State-Event Methods
State-Event Graphs
Example
P1
P2
C
Prepare
Prepare
Yes
Yes
Commit
Commit
Ack
Ack
18/22
19
Declarative Modeling
Hybrid State-Event Methods
Petri Networks
Properties

• Marks are used

• Transitions are dependent on places

Features

• Modeling of dynamic or concurrent behavior

Usage

• Distributed systems

• Modeling of manufacturing

• Human task coordination (Dining philosophers)

19/22
20
Declarative Modeling
Hybrid State-Event Methods
Petri Networks
Example
Server
Free
Busy
Client1
Client2
Petri network of a client-server process
20/22
21
Declarative Modeling
Conclusion

• Many different approaches for Declarative
  Modeling

• Even more modeling techniques

• Used in many areas from liguistics to computer
  science

21/22
22
Declarative Modeling
Questions
? ? ?
22/22