chapter 10 system engineering

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These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001

Chapter 10Chapter 10System System

EngineeringEngineering

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The The HierarchyHierarchy

World view

Business orProduct Domain

Domain of interest

Domain view

System element

Element view

Detailed view

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Business Process Business Process EngineeringEngineering uses an integrated set of procedures, uses an integrated set of procedures,

methods, and tools to identify how methods, and tools to identify how information systems can best meet the information systems can best meet the strategic goals of an enterprisestrategic goals of an enterprise

focuses first on the enterprise and then on focuses first on the enterprise and then on the business areathe business area

creates enterprise models, data models and creates enterprise models, data models and process modelsprocess models

creates a framework for better information creates a framework for better information management distribution, and controlmanagement distribution, and control

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The BPE The BPE HierarchyHierarchy Information strategy planning (ISP)Information strategy planning (ISP)

strategic goals definedstrategic goals defined success factors/business rules identifiedsuccess factors/business rules identified enterprise model createdenterprise model created

Business area analysis (BAA)Business area analysis (BAA) processes/services modeledprocesses/services modeled interrelationships of processes and datainterrelationships of processes and data

Application EngineeringApplication Engineering a.k.a ... software engineeringa.k.a ... software engineering modeling applications/procedures that address modeling applications/procedures that address

(BAA) and constraints of ISP(BAA) and constraints of ISP Construction and deliveryConstruction and delivery

using CASE and, testingusing CASE and, testing

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Information Strategy Information Strategy PlanningPlanning Management issuesManagement issues

define strategic business define strategic business goals/objectivesgoals/objectives

isolate critical success factorsisolate critical success factors conduct analysis of technology impactconduct analysis of technology impact perform analysis of strategic systemsperform analysis of strategic systems

Technical issuesTechnical issues create a top-level data modelcreate a top-level data model cluster by business/organizational areacluster by business/organizational area refine model and clusteringrefine model and clustering

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Defining Objectives and Defining Objectives and GoalsGoals Objective—general statement of directionObjective—general statement of direction

Goal—defines measurable objective: “reduce Goal—defines measurable objective: “reduce manufactured cost of our product”manufactured cost of our product” Subgoals:Subgoals:

decrease reject rate by 20% in first 6 monthsdecrease reject rate by 20% in first 6 months gain 10% price concessions from suppliersgain 10% price concessions from suppliers re-engineer 30% of components for ease of re-engineer 30% of components for ease of

manufacture during first yearmanufacture during first year

objectives tend to be strategic while goals objectives tend to be strategic while goals tend to be tacticaltend to be tactical

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Business Area Business Area AnalysisAnalysis define “naturally cohesive groupings of define “naturally cohesive groupings of

business functions and data” business functions and data” perform many of the same activities as ISP, perform many of the same activities as ISP,

but narrow scope to individual business areabut narrow scope to individual business area identify existing (old) information systems / identify existing (old) information systems /

determine compatibility with new ISP modeldetermine compatibility with new ISP model define systems that are problematic define systems that are problematic defining systems that are incompatible defining systems that are incompatible

with new information modelwith new information model begin to establish re-engineering prioritiesbegin to establish re-engineering priorities

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The BAA The BAA ProcessProcess

salesacct

manufacturing

QC

eng’ring

distribution

admin.

DataModel

ProcessDecomp.Diagram

Matricese.g.,

entity/processmatrix

Process Flow

Models

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Product Product EngineeringEngineering

System analysis(World view)

The completeproduct

capabilities

Componentengineering

(Domain view)

Processing requirement

Analysis & DesignModeling

(Element view)

Construction&

Integration(Detailed view)

software

function

SoftwareEngineering

programcomponent

hardware

data behavior

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Requirements Requirements EngineeringEngineering

ElicitationElicitation — determining what the — determining what the customer requirescustomer requires

Analysis & negotiationAnalysis & negotiation — — understanding the relationships understanding the relationships among various customer requirements among various customer requirements and shaping those relationships to and shaping those relationships to achieve a successful resultachieve a successful result

Requirements specificationRequirements specification — building — building a tangible model of requirementsa tangible model of requirements

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Requirements Requirements EngineeringEngineering

System ModelingSystem Modeling — building a — building a representation of requirements that representation of requirements that can be assessed for correctness, can be assessed for correctness, completeness, and consistencycompleteness, and consistency

ValidationValidation — reviewing the model — reviewing the model ManagementManagement — identify, control and — identify, control and

track requirements and the changes track requirements and the changes that will be made to themthat will be made to them

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Product Architecture Product Architecture TemplateTemplate

user interface processing

inputprocessing

outputprocessing

maintenance and self-test

process and controlfunctions

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Architecture Flow Architecture Flow DiagramDiagram

bar codereader

subsystem

bar codedecoding

subsystem

data baseaccess

subsystem

shuntcontrol

subsystem

reportformating

subsystem

diagnosticssubsystem

operatorinterface

subsystem

shuntcontroller

mainframecommunications

driver

operator requests CLSS queries, reports, displays

shunt control statusbar code acquisition request

bar code

pulse tach input

linespeed

bar codereader status

sensor status

raw barcode data

partnumber

reportrequests

binlocation

key

sort records

formatedreporting data

sorting reports

shunt commands

CLSS reports

BCR statusshunt status

communications status

timing/location data

operatorinterface

data acquisitioninterface diagnostic interface output interface

CLSS processing & control

sensor dataacquisitionsubsystem

chapter 10 system engineering

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