Eight deadly defects insystems engineering and

how to fix themDr Joseph Kasser

Leverhulme Visiting ProfessorCranfield University

j.kasser@cranfield.ac.uk

Agenda1. Selection of independent alternative solutions2. The V Model3. Lack of a standard process for planning a project4. The Waterfall model5. Unanswered and unasked questions6. Lack of a metric for the goodness of Requirements7. Focus on technological solutions not solving

customer’s problems8. The need to focus on people as well as process• Summary• Questions and discussion

3

The selection ofindependent alternative

solutions• The systems engineering process has

identified three alternative candidatesolutions (A, B and C)

• “C” gets the highest score• Which one is the optimal?• Possibly none of them• Possibly a combination of the best parts of

all of them

The “V” Model

5

Defects in the VModel

• Lacks ‘prevention of defects’• Definition of successful test?• Design works from requirements• T&E work from the need• T&E identify defects and plan to find them

after they have been built into the system• Why not prevent the defects?

* Kasser 1995

6

The Project Cycle

DesignRequirement

Test

Acceptancecriteria

(property of a requirement)

7

Prevention of defectiverequirements

• Requirements Workshopat UMUC and UniSA

• FRED and Tiger Pro• Figure of Merit for

document• Produced attitude

change in student’sperceptions

• Produced betterrequirements

8

Lack of a standard processfor planning a project

Determination of objectives Determination of Resources

Generate preliminary work plan (risks)

Draft work plan version 1

9

Lack of a standard processfor planning a project

Determination of objectives Determination of Resources

Identify and study lessons learned from previous projects

Negotiate objectives and resources

Generate preliminary work plan (risks)

Draft work plan version 1

10

The Waterfall model• Waterfall approach does not cope well with

changing requirements.• Change the production process from the

waterfall approach to some type of rapid, spiral,or other methodology– Iterative waterfalls– Spiral focuses on Risk Management

• Result– Some improvement

• comparing Chaos 1995 with Chaos 2004

11

Contract award

Vision of product

Intermediate milestones(product reviews)

Waterfall

Desired

Assumption behindWaterfall model

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Contract award

Vision of product

Intermediate milestones(product reviews)

Waterfall

Desired(moving target)

Real world ofchanges

13

Contract award

Visions of product (converge)

Intermediate milestones(product reviews)Configuration Control(Stage Gates)

Cataracts

Desired (keep youreye on the balls)

Assumptions behindCataract model

14

Unanswered andunasked questions

• Unanswered questions– Can you tell if the project is in trouble?– What percentage of the project is complete?

• Unasked questions at SRR– Are requirements with the following properties

really needed?• High cost, high risk• Low priority, high cost• Low priority, high risk

– Is this projected risk profile industry standard?

15

Project Priority profiles(object-orientedrequirements)

Why are weinvesting inthis system?

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Project Risk profiles(object-orientedrequirements)

Risk: Is thisreasonable?

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Most successful IS ofthe 20th century?

• RAF Battle of BritainCommand, Control, &Communications System– No computers– Germany had better

Radar Technology– RAF evolved and used

an integrated system– Adequate technology

• System?• System of Systems?• Complex System?• Network enabled system?

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Not solvingcustomer's problems

• “the systems engineer is primarily interested in making equipmentchanges” [Goode and Machol, 1959] page 130).

• The problem the executive had was to secure at alltimes, live and accurate data concerning the exactconditions of the business. [Farnham, 1920] page 20)

• [Beer, 1972] page 244) describes a conceptual system.– British War Room in the Battle of Britain– NASA’s control room at the Manned Space Flight Center in Houston,

Texas.– bits and pieces of it existed at that time.

• Beer proposed a control centre• Today’s technology allows for personal desktop portals accessing

information via software agents in an integrated digital or networkcentric environment.

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Complex orcomplicated?

20

The need to focus onpeople as well as process

• Literature– Is full of advice as to

how to make projectssucceed

– Has little if anything tosay about theproliferating processstandards

21

The need to focus onpeople as well as process

• Systems engineering is a way of life– (Hitchins 1998)– Integration of

• Schedules• Design, Testing and Integration• Systems of Systems divide?

• Are we focusing on the right things?– The Standards do not provide metrics that can

predict the failure of a project.• (K&W, 1998)

Summary Selection of independent alternative solutions The V Model Lack of a standard process for planning a

project The Waterfall model Unanswered and unasked questions Lack of a metric for the goodness of

Requirements Focus on technological solutions not solving

customer’s problems The need to focus on people as well as

process

Questions?