tools for innovation: the design structure matrix
TRANSCRIPT
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Tools For Innovation:The Design Structure Matrix
Thomas A. Roemerand Steven EppingerSummer 02, 15-761
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OutlineOverview
Traditional Project Management Tools and Product Development
Design Structure Matrix (DSM) BasicsHow to createClassification
The Iteration Problem: Increasing Development SpeedSequencing, Partitioning and Simulation
The Integration Problem: DSM ClusteringOrganizational Structures & Product Architectures
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Classical Project Management Tools
Gantt Charts
Graph-based: PERT, CPM, IDEF
Act
ivity
Time
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CharacteristicsComplex DepictionFocus on Work Flows
DSM focuses on Information FlowsIgnore Iterations & Rework
Test results, Planned design reviews, Design mistakes, Coupled nature of the process
Decomposition & IntegrationAssume optimal Decomposition & StructureIntegration of Tasks not addressed
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Design IterationIteration: The repetition of tasks due to new information.
Changes in input information (upstream)Update of shared assumptions (concurrent)Discovery of errors (downstream)
Fundamental in Product developmentOften times hidden
Understanding Iterations requires Visibility of information flows
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Decomposition and Integration
Decomposition: Dividing a complex problem into smaller sub-problems.
Integration:Combining sub-problems to achieve set goals.
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A Graph and its DSM
A C
D
B
H
F
G
E
I
A B C D E F G H IA A XB B XC X CD D XE EF X F XG GH X X HI X I
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Creating a DSMDesign manualsProcess sheetsStructured expert interviews
Interview engineers and managersDetermine list of tasks or parametersAsk about inputs, outputs, strengths of interaction, etcEnter marks in matrixCheck with engineers and managers
Questionnaires
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Four Types of DSMsIteration
Activity based DSMParameter based DSM
SequencingPartitioningSimulation
IntegrationTeam based DSMProduct Architecture DSM
Clustering
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Iteration Focused Tools
Concepts, Examples, Solution Approaches
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Sequencing Tasks in Projects
Possible Relationships between Tasks
A
B
A
B
A B
Dependent(Series)
Independent(Parallel)
Interdependent(Coupled)
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Sequencing AlgorithmStep 1: Schedule tasks with empty rows firstStep 2: Delete the row and column for that taskStep 3: Repeat (Go to step 1)Step 4: Schedule tasks with empty columns lastStep 5: Delete the row and column for that taskStep 6: Repeat (Go to step 4)Step 7: All the tasks that are left unscheduled are coupled. Group them into blocks around the diagonal
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Task Sequencing Example
Figure 4 at: http://faculty.erau.edu/ericksol/projects/futurspcrft/kristof/SPfinal.html
Space Shuttle Main Engine
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Product Decomposition
Engine Components
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Turbo Pump
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Project Scope
Activity
SM
SW
W
M W
Activity
Activ
ity
II
I II
I I
Information
Activ
ity
M
M
I
II
Verify A-A & A-I Matrices
Verify A-A & A-I Matrices
Verify OA-
Diagram
Verify OA-
Diagram
Organized Activity Diagram
Questionnaire
I
Gate Reviews
II III IV
Stage Overlapping
...
ConsultKey Functions
and Clients
ConsultKey Functions
and Clients
Time Cost Trade-Offs
ConsultKey Functions
and Executives
ConsultKey Functions
and Executives
OpportunityCosts
OpportunityCosts
Final Process Structure
SensitivityAnalysis
SensitivityAnalysis
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Corresponding LiteratureStructuring Product Development Processes
Ahmadi, Roemer & Wang, European J. of Operational Research 2001
Structuring Product Development ProcessesAhmadi, Roemer & Wang,
European J. of Operational Research 2001
Managing Development Risk in ProductDesign Processes
Ahmadi & Wang, Oper. Res. 1999`
Managing Development Risk in ProductDesign Processes
Ahmadi & Wang, Oper. Res. 1999`
Time-Cost Trade-Offs in Overlapped ProductDevelopment Processes
Roemer, Ahmadi & Wang, Oper. Res. 2000
Time-Cost Trade-Offs in Overlapped ProductDevelopment Processes
Roemer, Ahmadi & Wang, Oper. Res. 2000
...
Accelerating Product Development Roemer & Ahmadi, In review at Oper. Res.
Accelerating Product Development Roemer & Ahmadi, In review at Oper. Res.
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Finding Coupled StagesBlock
Creation
Block Decomposition
Design Time Computation
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Dependency Relations in Conceptual Design Block
For this graph, seeTime-Cost Trade-Offs in Overlapped ProductDevelopment Processes by Roemer, Ahmadi & Wang, Operations Research, 2000.
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Block Decomposition
∑∈Aij
ijijij ynamin
∑=
∀=M
mim ix
1 ,1
mCxN
iim ,
1∀≤∑
=
mjiyxxM
mhijjhim ,, ,0
1∀≤−− ∑
+=
{ } mj iyx ijim ,, ,1,0, ∀∈
s.t.
i,j = index for activities, i,j = 1,2,…,N;
m = index for stages, m = 1,2,…,M;
A = the set of directed arcs in the design graph;
aij = the level of dependency of activity i on j
⎩⎨⎧ =
=otherwise1
1if number) large (a aWn ij
ij
⎩⎨⎧
=otherwise0
stage toassigned is activity if1 mixim
⎩⎨⎧
=otherwise1
stagesbetween back feed a is arc if0 ijyij
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Resulting Structure for Conceptual Design Block
For this graph, seeTime-Cost Trade-Offs in Overlapped ProductDevelopment Processes by Roemer, Ahmadi & Wang, Operations Research, 2000.
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Lead Time Estimation
( )[ ]∑−
=
−− −++=1
1
00/11i
ii
n
niiiii etttetT
µλβ
( ) 1−−= PIjiµ
∑ ==
k
i iTT1
Exp. Iterations
Activity Duration
Stage Duration
Markov Chain
.3
S
21 3
.2.5
.51
T
1 .5
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Decomposition and Duration
0%
20%
40%
60%
80%
100%
0 5 10 15 20 25 30
Decomposition Degree (Number of Process Stages)
Blo
ck D
urat
ion
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Stage Size and Duration
Number of Activities
1 2 3 4 5 6 7 8 9 10 11
Number of IterationsDuration
0%
200%
400%
600%
800%
1000%
05101520253035
Dur
atio
n In
crea
se
Num
ber o
f Ite
ratio
ns
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Task A
Task B
Task C
X
X
X
DSM Simulation
Task A requires input from task CPerform A by assuming a value for C’s outputDeliver A’s output to BDeliver B’s output to CFeed C’s output back to A
Check initial assumption (made by A)
Update assumption and repeat task A.
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Simulating Rework
Task A
Task B
Task C
X
X
R
R is the probability that Task A will be repeated once task C has finished its work.
R = 0.0 : There is 0 chance that A will be repeated based on results of task C.R = 1.0 : There is 100% probability that A will be repeated based on results of task C.
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Simulating 2nd Order Rework
Task A
Task B
Task C
R2
X
X
Second Order rework is the rework associated with forward information flows that is triggered by feedback marks.
First order rework: Output of task C causes task A to do some rework2nd order rework: Consequently there is a chance tasks depending onA (e.g. task B) will also be repeated.
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Simulating Rework Impact
Task A
Task B
Task C
X
X
I
I = 0.0 : If task A is reworked due to task C results, then 0% of task A’s initial duration will be repeated
I = 1.0 : If task A is reworked due to task C results, then 100% of task A’s initial duration will be repeated
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Simulation Results
DSM contains rework probabilities and impactsCost and time add upMany runs produce a distribution of total time and costDifferent task sequences can be tried
Related reading: “Modeling and Analyzing Complex System Development Cost, Schedule, and Performance” Tyson R. Browning PhD Thesis, MIT A&A Dept., Dec 99
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Gantt Chart with Iteration
Typical Gantt chart shows monotone progressActual project behavior includes tasks stopping, restarting, repeating and impacting other tasks
Related Reading: “Modeling and Analyzing Complex System Development Cost, Schedule,and Performance” Tyson R. Browning PhD Thesis, MIT A&A Dept., Dec 99
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Lessons Learned: IterationDevelopment is inherently iterative.Understanding of coupling is essential.Iterations improve quality but consumes timeIteration can be accelerated through:
Information technology (faster iterations)Coordination techniques (faster iterations)Decreased coupling (fewer iterations)
Two Types of Iteration:Planned Iterations (getting it right the first time)Unplanned iterations (fixing it when it’s not right)
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Integration Focused Tools
Concepts, Examples, Solution Approaches
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Team SelectionTeam assignment is often opportunistic
“We just grab whoever is available.”
Not easy to tell who should be on a teamTradition groups people by functionInfo flow suggests different groupingsInfo gathered by asking people to record their interaction frequency with others
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Clustering a DSM
A B C D E F GA AB BC CD DE EF FG G
A F E D B C GA AF FE ED DB BC CG G
HiNo Dependency Low
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Alternative ArrangementOverlapped Teams
A F E D B C GA AF FE ED DB BC CG G
A F E D B C GA AF FE ED DB BC CG G
HiNo Dependency Low
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GM’s Powertrain Division22 Development Teams into four System Teams
Short block: block, crankshaft, pistons, conn. rods, flywheel, lubricationValve train: cylinder head, camshaft and valve mechanism, water pump and coolingInduction: intake manifold, accessory drive, air cleaner, throttle body, fuel systemEmissions & electrical: Exhaust, EGR, EVAP, electrical system, electronics, ignition
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Lessons Learned: IntegrationLarge development efforts require multiple activities to be performed in parallel.The many subsystems must be integrated to achieve an overall system solution.Mapping the information dependence reveals an underlying structure for system engineering.Organizations and architectures can be designed based upon this structure.
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Conclusions
The DSM supports a major need in product development:
documenting information that is exchanged
It provides visually powerful means for designing, upgrading, and communicating product development activitiesIt has been used in industry successfully
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DSM Web Pagehttp://web.mit.edu/dsm/It contains
A tutorialLinks to other DSM sitesOver 100 references of DSM literatureAnalysis tools
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Suggested Reading
“Innovation at the Speed Of Information”
By Steven D. Eppinger
HBR January 2001