CS 564 – Problem AnalysisLecture 8

Five Steps in Problem Analysis

• Gain Agreement on Problem Definition

• Understand Root Causes

• Identify the Stakeholders and the Users

• Define the Solution System Boundary

• Identify the Constraints to be Imposed on the Solution

Problem Statement Format

• The Problem of :• affects:

• the result of which:

• Benefits of:

• Describe the problem• Identify Stakeholders

affected by the problem

• Describe the impact of this problem on stakeholders and business activity.

• Indicate the proposed solution and list a few key benefits

Understand Root Cause

Too Much Scrap!

Custom

er returns

Dam

aged in

Shipm

ent

Inaccurate Sales

Orders

Fin

ishe

d G

oods

Obs

oles

cenc

e

Man

ufac

turin

g D

efec

ts

Oth

er

Addressing Root Cause

0

5

10

15

20

25

30

35

40

45

50

Contributions

Inaccuate SalesOrders

Damaged inShipment

Customer Returns

Finished GoodsObsolescence

ManufacturingDefects

Other

Identify the Stakeholders and Users

• Who are the users of the system?• Who is the customer (economic buyer) for the

system?• Who else will be affected by the outputs that the

system produces?• Who will evaluate and bless the system when it is

delivered and deployed?• Are there any other internal or external users of the

system whose needs must be addressed?• Who will maintain the system?• Is there anyone else?

Define the Solution System Boundary

SystemInputs Outputs

OurSolution

Users

I/O

System Boundary

Other SystemsI/O

Identify Constraints

• Economic

• Political

• Technical

• System

• Environmental

• Schedule and Resources

Proposed System

Proposed System

Check Status

Create Order

Shipment Notice

Inventory

Assign Inventory to Order

Inventory Assigned

New Inventory for Held Orders

Assign Order to Truck

Truckload Report

Shipping Invoices

Order Update

Order Display

Problem ResolutionDispatch

Accounting

Management Reports

Customer

Check Credit &

Completion

Users

Catalog

Orders

OrderCreation

Credit Check

InventoryAssignment

Held OrderProcessing

Completion

DispatchSupport

ProblemResolution

ManagementReporting

OA&M

Software Costing

Attribute Simple Average ComplexInputs (I) 3 4 6Outputs (O) 4 5 7Data Files {F} 7 10 15Interfaces (N) 5 7 10Inquiries (Q) 3 4 6

Complexity Ratings

Basic Function Point Type Count Complexity UFPOrder Processing Order Entry logon N 1 7 7 create order N 1 7 7 add item N 1 7 7 checkout N 1 7 7Order Status I 1 4 4Shipping Notice Q 1 7 7Credit Check N 1 10 10Inventory Processing Assign Inventory N 1 10 10Held Order N 1 10 10Problem Resolution Display Q 1 3 3Update/Create Order I 1 6 6Dispatch 0Assign to Truck I 1 4 4Truck Report Q 1 4 4Shipment Invoice Q 1 4 4Completion N 1 7 7Reports Q 10 4 40FilesUsers F 1 10 10Catalog F 1 10 10Orders F 1 15 15OA&MTransactions I 5 4 20Reports Q 5 4 20Tables F 10 7 70Outputs O 5 4 20

Total Unadjusted Function Points 302

General System Characteristic Rating1 Data Communications 22 Distributed Data/Processing 23 Performance Objectives 24 Heavily Used Configuration 35 Transaction Rate 16 On-Line Data Entry 47 End-User Efficiency 58 On-Line Update 59 Complex Processing 2

10 Reusability 211 Conversion/Installation Ease 412 Operational Ease 413 Multiple Site Use 414 Facilitate Change 4

Total Degree of Influence 44

UFP (.65+.01*TDI)302 1.09

Adjusted Function Points 329

Software Costing

• Cost Development using FPA

• Estimate • Requirements

Engineering (1/3 of development

• Design (1/5 of development)

• Testing (1/4 of development

• Documentation & Training

FP per mo 5Dev Staff Mos 65.8Dev Staff Yrs 5.5Sys Eng 1.8Design 1.1Test 1.8Doc 1.0Trng 1.0Total 12.2

Staff Cost $150,000Project Cost $1,836,173

Opportunity Assessment Context

CustomerBusiness

Case

= NPV = (Benefits, Time) - (Costs, Time)

ProductBusiness

Case

= NPV = (Revenue, Time) - (Costs, Time)

(Price, Market Size)

Software CostEstimation

(Hardware)

Units

Setting PriceElement License Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Total

Usage Block 200000 Units 3 9 12 12 12

RevenueOM License $599,000 $1,797,000 $5,391,000 $7,188,000 $7,188,000 $7,188,000 $28,752,000Amoritization $0 $0 $0 $0 $0 $0 $0 $0Other COS 36% $646,920 $1,940,760 $2,587,680 $2,587,680 $2,587,680 $10,350,720 Total Incurred Costs $646,920 $1,940,760 $2,587,680 $2,587,680 $2,587,680 $10,350,720

$0Margin $0 $1,150,080 $3,450,240 $4,600,320 $4,600,320 $4,600,320 $18,401,280% Margin 64% 64% 64% 64% 64% 64%

$0Expenses $0Actual R&D $1,836,173 $300,000 $2,136,173Capitalized R&D $0 $0R&D $1,836,173 $300,000 $0 $0 $0 $0 $2,136,173 Marketing/Sales 25% $0 $449,250 $1,347,750 $1,797,000 $1,797,000 $1,797,000 $7,188,000 Distribution $0 G & A 8% $0 $143,760 $431,280 $575,040 $575,040 $575,040 $2,300,160 Total Expenses $1,836,173 $893,010 $1,779,030 $2,372,040 $2,372,040 $2,372,040 $11,624,333

$0Other Income $0

$0Operating Income -$1,836,173 $257,070 $1,671,210 $2,228,280 $2,228,280 $2,228,280 $6,776,947

OROS 14.3% 31.0% 31.0% 31.0% 31.0% 23.6%

Capitalizing Software

Balance Sheet

Assets

Capitalized SW

Liabilities

Balance Sheet

Assets

Capitalized SW

Liabilities

Income Statement

RevenueCost of Sales Amoritization

ExpensesR&D Capitalized SW

Income Statement

RevenueCost of Sales Amoritization

ExpensesR&D Capitalized SW

Capitalize

Amoritize

Gossamer Balance SheetPeriod Ending 31-Dec-02 30-Sep-02 30-Jun-02 31-Mar-02

    Cash And Cash Equivalents $9,677,091 $9,443,970 $12,675,030 $14,489,818     Short Term Investments $48,126,424 $41,980,545 $38,313,939 $39,457,818     Net Receivables $12,057,939 $12,063,212 $11,662,000 $11,474,303     Inventory N/A N/A N/A N/A    Other Current Assets $1,377,212 $1,517,182 $1,671,303 $1,796,091 Total Current Assets $71,238,667 $65,004,909 $64,322,273 $67,218,030

    Long Term Investments $665,030 $2,022,182 $3,826,515 $1,289,061     Property Plant And Equipment $6,751,515 $6,833,364 $6,838,152 $6,580,303     Goodwill $1,645,273 $1,640,303 $1,610,061 $1,478,970     Intangible Assets $1,336,394 $1,464,000 $1,438,424 $655,606     Accumulated Amortization N/A N/A N/A N/A    Other Assets $162,394 $634,939 $695,182 $713,394     Deferred Long Term Asset Charges $4,520,818 $3,491,455 $4,549,273 $2,880,636 Total Assets $86,320,091 $81,091,152 $83,279,879 $80,816,000

    Payables And Accrued Expenses $10,707,515 $9,504,242 $10,584,970 $10,534,697     Short Term And Current Long Term Debt N/A N/A $1,727,273 $1,727,273     Other Current Liabilities $12,807,788 $11,878,303 $12,995,212 $12,763,576 Total Current Liabilities $23,515,303 $21,382,545 $25,307,455 $25,025,545     Long Term Debt N/A N/A N/A N/A    Other Liabilities $651,091 $632,030 $673,818 $683,394     Deferred Long Term Liability Charges $2,892,727 $2,822,364 $2,925,485 $3,120,576     Minority Interest N/A N/A N/A N/A    Negative Goodwill N/A N/A N/A N/ATotal Liabilities $27,059,121 $24,836,939 $28,906,758 $28,829,515

Current Liabilities

Current Assets

Long Term Assets

Gossamer Income Statement Period Ending: 31-Dec-02 30-Sep-02 30-Jun-02 31-Mar-02Total Revenue $15,522,909 $14,279,182 $14,612,485 $14,644,455 Cost Of Revenue $5,395,879 $5,177,364 $5,495,182 $5,537,030 Gross Profit $10,127,030 $9,101,818 $9,117,303 $9,107,424 Margin 65.2% 63.7% 62.4% 62.2%

    Research And Development $2,675,909 $2,515,212 $2,652,939 $2,494,939     Selling General And Administrative Expenses $5,110,485 $4,692,424 $4,653,273 $4,691,394     Non Recurring ($36,485) N/A $263,000 $84,848     Other Operating Expenses N/A N/A N/A N/ATotal Operating Expense $7,749,909 $7,207,636 $7,569,212 $7,271,182

Operating Income $2,377,121 $1,894,182 $1,548,091 $1,836,242 Total Other Income And Expenses Net $345,667 $169,909 $256,909 $219,364 Earnings Before Interest And Taxes $2,722,788 $2,064,091 $1,805,000 $2,055,606 Operating Return on Sales (OROS) 17.5% 14.5% 12.4% 14.0%

Operating Expenses

Net Income Applicable To Common Shares $1,739,697 $1,351,970 $1,091,515 $1,349,818 Shares outstanding 6000000 6000000 6000000 6000000Earnings per Share $0.290 $0.225 $0.182 $0.225Share Price at end of period $6.47 $5.95 $6.09 $6.10

Absorbing the project will substantially reduce Operating Income => Capitalize

CapitalizationElement License Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Total

Usage Block 200000 Units 3 9 12 12 12

RevenueOM License $599,000 $1,797,000 $5,391,000 $7,188,000 $7,188,000 $7,188,000 $28,752,000Amoritization $1,000,000 $21,000 $63,000 $189,000 $252,000 $252,000 $244,000 $1,000,000Other COS 36% $646,920 $1,940,760 $2,587,680 $2,587,680 $2,587,680 $10,350,720 Total Incurred Costs $709,920 $2,129,760 $2,839,680 $2,839,680 $2,831,680 $11,350,720

$0Margin $0 $1,087,080 $3,261,240 $4,348,320 $4,348,320 $4,356,320 $17,401,280% Margin 60% 60% 60% 60% 61% 61%

$0Expenses $0Actual R&D $1,836,173 $300,000 $2,136,173Capitalized R&D $1,000,000 $1,000,000R&D $836,173 $300,000 $0 $0 $0 $0 $1,136,173 Marketing/Sales 25% $0 $449,250 $1,347,750 $1,797,000 $1,797,000 $1,797,000 $7,188,000 Distribution $0 G & A 8% $0 $143,760 $431,280 $575,040 $575,040 $575,040 $2,300,160 Total Expenses $836,173 $893,010 $1,779,030 $2,372,040 $2,372,040 $2,372,040 $10,624,333

$0Other Income $0

$0Operating Income -$836,173 $194,070 $1,482,210 $1,976,280 $1,976,280 $1,984,280 $6,776,947

OROS 10.8% 27.5% 27.5% 27.5% 27.6% 23.6%

Customer Benefits

• Customer Business Case• Very strong cash flow• Strategic for customer

Element Year 0 Year 1 Year 2 Year 3 Year 4 Year 5 NPV Interest($K) ($K) ($K) ($K) ($K) ($K) ($K) 0.028

Year 0 1 2 3 4 5 1/(1+I)**n 1.000 0.973 0.946 0.920 0.895 0.871

Operations Savings $3,977,727 $0 $3,869 $3,764 $3,661 $3,562 $3,465 $18,321 PMO per Order $40.40 FMO per Order $18.65 Orders per Year 182884Hardware Costs $35 $35 $5 $5 $5 $5 $5 $60 Hardware $30 Maintenance (18%) $5Software Costs $599 $599 $599Services $216 $216 $216

Cash Flow ($850) $3,864 $3,759 $3,657 $3,557 $3,460 $17,446 NPV

Risks

• Too Good to Be True• Study at next level of detail

• New Customer, New Problem Domain• High diligence on requirements• Create friendly customer arrangement

• Minor risk with hardware selection• Convince customer for forward sizing

Opportunity Assessment

• Quantify the model• Improves your understanding of the value• Improves your understanding of the business

• Refine estimates that matter• Hardware was pretty inconsequential in this case

study• Stepwise refinement to get to investment

decisions

• A quantified model can drive your investment

Software Requirements Taking Stock

Now on to:

• Requirements Synthesis

• Technology Investment

• Requirements Selection

• Requirements Homework

Requirements Engineering Process

Requirements ElicitationRequirements Elicitation

Requirements Analysis & Negotiation

Requirements Analysis & Negotiation

Agreed Requirements

Draft Requirements Document

Requirements Document & Validation Report

Informal Statement of Requirements

Decision Point: Accept Document or re-enter spiral

Requirements SpecificationRequirements Specification

Requirements ValidationRequirements Validation

• Process Models• Process Actors and

Stakeholders• Process Support

and Management• Process Quality and

Improvements• Relationship to the

Business Decision

Requirements Process - Context

• Varied Sources• Functional• NonFunctional• Risk Factors

• Continuity• Strategic• Process & Project

• Varied “Consumers”• Development• Marketing• Training & Documentation• Information Base

RequirementsEngineering

Process

BusinessStrategy

BusinessStrategy

TechnologyStrategy

TechnologyStrategy

Project, Process & DocumentationStandards

Project, Process & DocumentationStandards

OpportunityAnalysis

MarketAnalysis

CustomerRequest

SoftwareDesign

SoftwareDevelopment

SoftwareTesting

Requirements Document

Requirements Document

Marketing,Etc.

Yet another Software Requirements Document Structure

Prospectus Describe the need for the system. Describe system functions and

rationale for the software and the MOVThe System Model

Set out full system model, showing the relationships between the system components. An abstract data model should also be described.

System Evolution Describe fundamental assumptions on which the system is based and

describe anticipated changes due hardware evolution, changing user needs,etc.

Functional Requirements The services provided for the user are described using natural

languages with cross references to the requirements specification. Non-functional Requirements

The constraints imposed on the software operation and restrictions on the design.

Glossary

Requirements Process

• Elicitation• Request Analysis

• Sourcing & Screening

• Definition• Purposeful• Understand value

• Analysis• Interrelationships• Prioritization• Risk & Cost Assessment

• Specification• Modeling

• Validation• Agreement

• Change Management

RequestAnalysis

RequirementsDefinition

RequirementsAnalysis

RequirementsSynthesis

RequirementsSpecification

RequirementsValidation

Req

uirm

ents

Cha

nge

Man

agem

ent

Requirements Elicitation Review

Requirements Sources• Goals (Value)• Domain Knowledge• System

Stakeholders• Operational

Environment• Organizational

Environment

Elicitation Techniques• Interviews• Scenarios• Prototypes• Facilitated Meetings• Observation• Workshops

Interviewing

• Target Stakeholders• Usually appropriate for managers and

nonuser stakeholders

• Context Free Questions• Open not closed

• Preparation• Research company and person’s

background.

Observations

• Target Users• Observe work steps• Identify different use cases/scenarios

• Scope• Repetitive• Across target market

• Preparation• Operations background from local

management.

Workshops

• Target Users, user management, analysts, project management

• Baseline the team• Summary of Objectives and analyst

findings

• Trained Facilitator• Experienced in facilitating innovation

Levels of Customer Requirements

• Expecters• Customer assumes is

part of the product or service

• Spokens• Specific features the

customer desires

• Unspokens• Uncommunicated part of

customer’s expectation

• Exciters• Unexpected features

making the product unique

I assume it meets all federal, state, and local codes.

Expecters

3 car garage2 bedrooms

2 baths

Spokens

I’ll know it when I see it

Unspokens Exciters

Wow! A lifetime warranty on the

roof

Technology Strategy- NonFunctional

Technology Initiatives

Metric: Percent of Revenue due to new products for past three years

From Market From MarketingIdeas from StaffTechnology Assessments

Processes &Products (with embedded new Technology)

Inputs

Outputs

Roles in Technology Strategy

1. Executive CabinetCEOCTOCIOVPs

2. Chief Technology Officer3. Office of Technology Planning4. Development Teams

Executive Cabinet’s Job

•Assure that the Technology Plan is Consistent with the Strategic Plan

•Hire a CTO who can be an ‘out-of-the-box’ thinker

•Encourage and Reward Invention

•Stimulate Innovations from Inventions

CTO’s Job

• Lead the Office of Technology Planning• Create a Technology Vision • Fund Technology Trials and Jumpstarts• Approve and Communicate Initiatives• Integrate with Product Lines• Create R&D Personnel Policies• Chair Intellectual Property Team• Create a climate of Innovation: ‘the dither

index.’

Office of Technology Planning

• Recommend Technology Priorities• Assess Technology Payoffs• Drive to Asset Based Business: Platforms

& Components• Encourage Technology Transfer/ Diffusion• Professional Community Contacts• Foster Benchmarking

Development Teams

• Try new Technologies• Adopt and deploy sanctioned

technologies• Avoid maverick technologies• Embrace the Technology Plan

Innovation Process

Make or Buy ?

Plan

MOV: 1. 20 % of revenue derived from new

products in every three year window 2. 20% productivity improvement per

decade

Acquire

Contract &Evaluate

Deploy

Prioritize

Innovation Process- with Feedback

Make or Buy ?

Plan

MOV: 1. 20 % of revenue derived from new

products in every three year window 2. 20% productivity improvement per

decade

Acquire

Contract &Evaluate

Deploy

Prioritize

Fullfilling Customer Requirements

Cu

stom

er Satisfactio

nL

ow

Hig

h

Achievement of RequirementsLow High

Expecters

Spokens

Unspokens

Exciters

As of 28 Oct

Six Aspects of Good Software Products

Systematic Prioritizing Requirements

Quality Function Deployment is a systematic good practice to setting priorities and tracing critical requirements in the software product realization process.

Quality Function Deployment

What is QFD?

• Integrates Design Process

• Maps Customer Requirements into• Definable & measurable product &

process parameters

• Format & Language can be used with customers

• Constructed to resolve divergent needs of the stakeholders

• Benefits• 30% to 50% reduction in

engineering changes• 30% to 50% shorter design cycles• 20% to 60% lower start up costs• 20% to 50% fewer warranty claims

CorrelationMatrix

TechnicalRequirements

(Hows)

Target MovementObjective

RelationshipMatrix

Whats

Imp

ort

an

ce R

atin

g

Cu

sto

me

r C

om

pe

titiv

eA

sse

ssm

en

t

Technical CompetitiveAssessment

(How Muches)

Absolute Score

Relative Score

Target Goals

House of Quality

Correlations

Technical Aspects

RelationshipsCustomer Needs Customer’s

Priority

Technical Aspect Importance

Quality Function Deployment

QFD Process

1. Define customer requirements

2. Determine requirement importance

3. Assess competitive position

4. Define Hows (Technical Requirements)

5. Define Target Goals

6. Determine correlation matrix elements

7. Assess competitor technical performance and set objective values

8. Complete the relationship matrix

9. Compute the absolute score

10. Determine relative ranking of the Hows

CorrelationMatrix

TechnicalRequirements

(Hows)

Target MovementObjective

RelationshipMatrix

Whats

Imp

ort

an

ce R

atin

g

Cu

sto

me

r C

om

pe

titiv

eA

sse

ssm

en

t

Technical CompetitiveAssessment

(How Muches)

Absolute Score

Relative Score

Target Goals

Example: Good Video Game

EasyTo Use Good

Visualeffects

Don’t getHurt

Playing

EverybodyCan use

itAffordable

SturdyControls

No eyestrain

VersatileControls

NotBreakEasily

InterruptablePlay

WideAssortmentOf Action

Objective: What are the qualities of a good video game?

EasyTo Use

GoodVisualeffects

Don’t getHurt

Playing

EverybodyCan use

it

Affordable

SturdyControls

No eyestrain

VersatileControls

NotBreakEasily

InterruptablePlay

WideAssortmentOf Action

GetMoney’sWorth

CompetitiveExcitement

SafeDesign

Example: Good Video Game

Objective: What are the qualities of a good video game?

Easy To Use

Good visual effects

Don’t get hurt playing

Everybody can use it

Affordable

Sturdy Controls

No eye strain

Versatile Controls

Not Break Easily

Interruptable Play

Wide AssortmentOf Action

GetMoney’sWorth

CompetitiveExcitement

SafeDesign

GoodVideoGame

Easy to UseNot break easilyVersatile controlsAffordableGood visual effectsEverybody can use itSturdy ControlsInterruptable PlayWide Assortment of ActionNo eye strainDon't get hurt using

Customer needs

Get

M

oney

's

Wor

th

Pro

vide

s C

ompe

titiv

e E

xcite

men

tS

afe

D

esi

gn

Importance Rating

• Voice of the Customer• Customer Participation or• Customer Advocate

• Consultants• Sales & Marketing

• Methods• Use a 1-9 rating system• Rate on initial pass• To Refine

• Rank Order• Distribute 100 points• Full Pairwise Comparison• Force uniform distribution• Priority inversion for case

where there is a pre-requisite

Impo

rtan

ce

Easy to Use 4Not break easily 3Versatile controls 2Affordable 3Good visual effects 5Everybody can use it 3Sturdy Controls 4Interruptable Play 2Wide Assortment of Action 5No eye strain 3Don't get hurt using 4

Customer needs

Get

M

oney

's

Wor

th

Pro

vide

s C

ompe

titiv

e E

xcite

men

tS

afe

D

esi

gn

Degree of Contribution

• Weak =1

• Moderate = 3

• Strong = 5

• Very Strong = 7

• Extreme = 9

Voice of the Customer

100Page RFP

Military RFP for a new Plane

Fly Higher………………….3Fly Faster………………….2Carry more Weight……….5Be more Maneuverable….4

First Cut Feature/Attribute Analysis

Easy Fly Higher

Fly

Faster

Less

Weight

More

Manu

Relib. 1 1 1 9 3

Faster

Soft.3 3 3 1 9

Mem.

Red.

5 1 1 9 1

Matrix Analysis-Judgment Applied

Easy Total E x T Priority Over-

ride

Relib. 1 14 14 3 1

Faster

Soft.3 16 48 2 3

Mem.

Red.

5 12 60 1 2

Competitive Position

• Rate Self• Rate Competitors• Set Planned Level• Compute Improvement

Ratio• Determine Sales Points• Determine Importance

Weight• (Importance *

Improvement Ration)

• Determine Relative Weight• Express Importance

Weight as a %

Cur

rent

Com

pany

Rat

ing

Com

petit

or A

Com

petit

or B

Pla

nned

Lev

el

Impr

ovem

ent

Rat

io

Sal

es P

oint

Impo

rtan

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eigh

t

Rel

ativ

e W

eigh

t

3 4 4 4 1.3 5.2 11.84 4 3 4 1.0 3.0 6.82 2 3 4 2.0 O 4.0 9.03 2 3 3 1.0 3.0 6.83 4 2 4 1.3 6.5 14.75 3 3 5 1.0 O 3.0 6.84 3 2 4 1.0 o 4.0 9.04 4 2 4 1.0 2.0 4.53 4 3 4 1.3 6.5 14.74 2 3 4 1.0 o 3.0 6.84 4 3 4 1.0 4.0 9.0

Total 44.2

Impo

rtan

ce

Easy to Use 4Not break easily 3Versatile controls 2Affordable 3Good visual effects 5Everybody can use it 3Sturdy Controls 4Interruptable Play 2Wide Assortment of Action 5No eye strain 3Don't get hurt using 4

Customer needs

Get

M

oney

's

Wor

th

Pro

vide

s C

ompe

titiv

e E

xcite

men

tS

afe

D

esi

gn

Technical Requirements (Hows)

• Cross Functional Team• Uses Customer

Requirements to Define Technical Requirements

• If I control “the how” then I am meeting my customers’ objective to “provide the what”.

• Collect data from• RFPs• Publications• Technical Interchanges

with customers

• Tier• Place details in subsystems

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Target Goals

• Quantify the Goal• Increase/Decrease• Specific Objective

• Product Test Rating• MTBF, Returns

• Unable to Quantify• Restate the technical

requirement• From Software Design• To Improved graphics or

improved responsiveness

Target Values No

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Target Goals X - + - + + - + + +

+ # ##-

+++#+

#++

# +++ -

#

Technical Interactions

• Correlation matrix• Shows interaction of

technical requirements• Positive correlation

• Implies synergy• Cost advantages

• Negative correlation• Tradeoffs required

• Revisit Technical Requirements• Remove technical

requirement negative correlation

• Alternative approaches

Impo

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Target Goals X - + - + + - + + +

++ Strong Positive+ Weak Positive- Weak Negative# Strong Negative

++ Strong Positive+ Weak Positive- Weak Negative# Strong Negative

Technical Competitive Assessment

• Rate Own Company on the Technical Requirements

• Rate Competitors and compare

Target Values No

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yOur Company 3 4 2 3 3 5 4 4 3 4Competitor B 4 4 2 2 4 3 3 4 4 2Competitor A 4 3 3 3 2 3 2 2 3 3

Technical Comparison

0123456

1 3 5 7 9

11

Our Company

Competitor B

Competitor A

Correlating Technical Requirements & Customer Needs

• Rate ability for Technical Requirement to satisfy customer need

• If I control (the technical requirement) it will (significantly/moderately/ slightly/or not) impact my customers needs to (specific customer need).

• Multiple rating systems• 9/3/1/0

• 5/3/1/0

• 4/2/1/0

Impo

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Target Goals X - + - + + - + + +

Easy to Use 4 5 5 3 3Not break easily 3 3 5 5Versatile controls 2 5 3 5Affordable 3 3 5 5 5 3 5 3 1 3Good visual effects 5 1 3 5 5Everybody can use it 3 3 1 3 5Sturdy Controls 4 3 5Interruptable Play 2 5Wide Assortment of Action 5 5 1 3 3 5 3 5No eye strain 3 5 5 5 5 5Don't get hurt using 4 5 3 3

Customer needs

Get

M

oney

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Wor

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Pro

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Scoring Results

• Compute absolute score• Weighted Importance of

Technical Requirements• Sum of correlation rating *

customer importance for a specific technical requirement

• Relative score• Weighted importance for a

technical requirement divided by total weighted importance (x100).

• Shows which technical requirements best satisfy customer needs

Impo

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Num

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Target Goals X - + - + + - + + +

Easy to Use 4 5 5 3 3Not break easily 3 3 5 5Versatile controls 2 5 3 5Affordable 3 3 5 5 5 3 5 3 1 3Good visual effects 5 1 3 5 5Everybody can use it 3 3 1 3 5Sturdy Controls 4 3 5Interruptable Play 2 5Wide Assortment of Action 5 5 1 3 3 5 3 5No eye strain 3 5 5 5 5 5Don't get hurt using 4 5 3 3

Weighted Importance 43 110 60 34 73 70 65 66 50 49Relative Weight 7 18 10 5 12 11 10 11 8 8

Customer needs

Get

M

oney

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Wor

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Pro

vide

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Requirements Request Analysis

Formalizing the Request• Clearly stated• Categorized

• Discretionary/Non-discretionary

• Cost/Benefit

• Business Strategy Alignment, e.g.,• Migration to e-business• Corporate data access

• Technology Strategy Alignment, e.g.,• Commitment to middleware• Data base technology

RequirementsRequest

RequestScreening

BusinessStrategy

BusinessStrategy

TechnologyStrategy

TechnologyStrategy

Alignment Screening

Source: Andriole, Stephen J., Managing System Requirements, Methods,

Tools, and CasesMcGraw-Hill, 1996

Source: Andriole, Stephen J., Managing System Requirements, Methods,

Tools, and CasesMcGraw-Hill, 1996

ImperativeImperative PotentialValue

PotentialValue

DiscardDiscard

Requirements Request Analysis

• Captures description and source

• Prioritization• References to Use

cases and other documents

Requirement #: Requirement Type: Event/UseCase #:

Description:

Rationale:

Source:

Fit Criterion:

Customer Satisfaction: Customer Dissatisfaction:

Dependencies: Conflicts:

Supporting Materials:

History:

Snow Cards

Requirements Synthesis

• When are you done?• Have a plan and execute to plan.

• Diversity of stakeholders and customers

• Track knowledge churn• Dates/sources on SNOW cards• Revise plan if you are still learning• You’re done when your base stabilizes

– I.e., interviews and observations are only clarifying known requirements

Analysis Approach

• Stakeholders• Organization

• PMO• Value Proposition• Context Diagram• FMO

• Role Playing

• “ilities”• Perfomance• Reliability• Maintainability, etc.

Organizing the Requirements

• Context Diagram• Current Operation• Identify Business Events

or Use Cases• Process Orientation

• Affinity Diagrams• Mind Maps• Functional Orientation

• Document Archaeology• Identifies “things”• Data Orientation

Context Diagram

Customer

Software Reliability Engineering

• The reliability of a system as a function of time R(t), is the conditional probability that the system has (not failed) in the interval [0,t], given that it was operational at time t=0

• The most common reliability model is:

R(t) = e-t,

• where is the failure rate. • It is reasonable to assume that the failure rate is

constant even though faults tend to be clustered in a few software components.

Two-state Reliability Model

• In a two-state continuous-time Markov chain the parameters to be estimated are failure rate and repair rate .

• The Mean Time Between Failures (MTTF) = 1/ . • The Mean Time To Repair (MTTR)= 1/.• Availability = MTTF/(MTTF +MTTR) = 1/[1 + /]

• The goal of Software Fault Tolerance is to make Availability = 1.• This can be approached by making very small and/or by

making very large.

Maximizing Availability

Decreasing • Best Practices

• Case Tools• Traceability• Inspections• Testing

• Architecture• Re-use• Platforms• Factoring• Failure Protection SW

Increasing • Architecture

• Fail-over• Restarts

Software Reliability Engineering

• List Associated Systems• Base product and variations• Supersystems

• Implement Operational Profiles• An operation is a major system

task (use case)• Occurrence probability

• Engineer “Just Right” Reliability• a failure as any departure of

system behavior in execution from user needs

• choose a common measure for all failure intensities

• set the total system failure intensity objective (FIO) for each associated system

Requirements and

Architecture

Design and Implementati

on

Test

1. List Associated Systems

2. Implement Operational Profiles

3. Engineer “Just Right” Reliability

4. Prepare for Test 5. Execute Test

6. Guide Test

Control System Reliability

• Control Systems• If the system fails because the

time constraints are not satisfied the system is a real-time one.

• If the response time becomes arbitrarily long the system is an on-line one.

• Reliable Software• Demands that the computations

are completed in the required time.

• System does not degenerate due to:

• computational lags in controlling external equipment,

• round-off errors in computing control commands,

• truncation errors induced when equations are approximated.

ExternalEquipment

ComputerContaining

ControlEquations

= x(n) – y(n-1)

x(n)

Delays

y(n)y(n-1)

Wherex(n) is the physical input to the external equipment that is sampled and encoded with a certain number of bits or precision.y(n) is the computer output from the computers control equations using the error from the previous sampled time as the input

Other Functions

Impact on Requirements

• Quantification of Operations (use cases)

• Reliability Requirements• By Operation• Estimation of Value

• Analysis of Control Equations• Impact of Timing Variations• Numerical Analysis and Requirements for

bounding behavior

Reliability Requirements

• Availability• Percent Available• Programmed down time.

• Mean Time Between Failure (MTBF)• Usually in hours• Careful specification of “failure”

• Mean Time to Repair (MTTR)• Profile (90% restored in 5 minutes)• Careful specification of “restore”

• Accuracy• Precision in numerical outputs

• Maximum bugs or defect rate• Bugs per KLOC or bugs per function point

• Bugs per type• Minor, significant, critical