Replacing Hardware With Software Analysis and simulation of existing hardware using Discrete Event...

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Replacing Hardware With Software

Analysis and simulation of existing hardware using Discrete Event System Specification.

By:Philip FelberAman GuptaImaduddin MohammedKwadwo Adomako

November 27, 2001Prepared for Dr. James StineECE 587 Hardware / Software CoDesignIllinois Institute of Technology

11/27/2001 ECE587 Replacing Hardware With Software 2

Philip – Set the scene

Large apartment buildings built in the seventies (before embedded computers) were equipped with custom electronic security and control systems.

Security Key Switch

Security On Package

(loudspeaker)

Apartment Security Panel

SecurityPackage NotificationFire AlarmEmergency

System componentsApartment security panels (in each unit)Central communications controllerAlarm “readout” at front deskKeypad terminal at receiving room

Today it’s increasingly hard to find both repair parts and technicians who understand this antiquated hardware.

With DEVS as a framework, this study analyzes and simulates a legacy security system and assesses opportunities to replace certain hardware components with software.

Aman – DEVS

The Discrete Event System Specification (DEVS) environment is a system based simulation tool that provides expandability with modular and hierarchical features and flexibility.

DEVS framework consists of: real system model simulator experimental frame These are related by two relations: modeling relation simulation relation

Source

System

Simulator

Behavior database

Modeling

Relation

Simulation

Relation

Experimental frame

In the DEVS formalism, there are two models to be specified:

Atomic Model from which larger models are built

Coupled Model

Atomic Model containsSet of input portsSet of output portsSet of state variables and parametersInternal transitionExternal transitionOutput function

Coupled Model must contain

Set of componentsSet of input ports Set of output portsCoupling specifications

Imaduddin – Specific analysis

Modeling with DEVSModeling with DEVS

States:Key Position

Emergency

Door Position

Package

InputEvents

OutputEvents

Outline the functions.

Identify the Input Events.

Intrusion

Identify Internal States.

Identify Output Events

Hierarchical Model of the SystemHierarchical Model of the System

Security Alarm

Emergency Alarm

FireAlarm

Apartment Panel

Package Notification from Receiving room

Central Communication Control

Key Door

Atomic Model

Coupled Model

Atomic Model

Alarms tofront desk

Simulation Start

Initialize States

Wait For Input Event

Input Event Occurs

Process the request Give output

Event Driven Program

Multithreaded

Modular

For Example:

PkgReceiveModule

Central CommunicationControl Module

AptPanel Module

Input Event

Package Arrival

OutputEvent

Set packageLight ON

State---------------- PkgBefore Input Event NOAfter Input Event -Yes

Kwadwo – Close the deal

What we have accomplished

Analysis of the system with DEVS formalism.Choose which components we can replace with software.Simulate the system.The DEVS simulation may develop into the actual production program.

Advantages of our Design

Our design makes the system faster. It provides room for further additions to the system.It is easier to maintain.

What’s yet to be done?

Complete the simulation program of the system in java.Complete documentation of the project.

Summary

Some parts of legacy hardware systems are candidates for emulation by software running on general purpose microprocessors.DEVS may be a useful tool for analysis and simulation.The DEVS simulation may develop into the actual production program.

Where To Get More Information

Zeigler, Praehofer, and Kim: Theory of Modeling and Simulation: Integrating Discrete Event and Continuous Complex Dynamic Systems, Academic Press, 2000. Search the ‘NET’ for DEVS.www.ece.iit.edu/~pfelber/devs/ibms/

Replacing Hardware With Software Analysis and simulation of existing hardware using Discrete Event...

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