constraint programming for supply chain management j. christopher beck cork constraint computation...
TRANSCRIPT
Constraint Programming for Constraint Programming for Supply Chain ManagementSupply Chain Management
J. Christopher BeckCork Constraint Computation Centre (4C)
SCM Information Day, Nov. 21/02
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OutlineOutline
What is Constraint Computation?– aka Constraint Programming (CP)
What does constraint computation have to do with supply chain management?
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A PuzzleA Puzzle
Place the numbers 1 through 8 in the nodes such that:– Each number appears exactly once
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– No connected nodes have consecutive numbers
You have 5 minutes!
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ModelingModeling
Each node a variable{1, …, 8} values in the domain of each
variableNo consecutive numbers a constraint
– (vi, vj) |vi – vj| > 1
All values used all-different constraint
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Heuristic SearchHeuristic Search
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?? 1 8
{1, 2, 3, 4, 5, 6, 7, 8}
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Inference/PropagationInference/Propagation
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?? 1 8
{1, 2, 3, 4, 5, 6, 7, 8}
{1, 2, 3, 4, 5, 6, 7, 8}
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Inference/PropagationInference/Propagation
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?? 1 8
{3, 4, 5, 6}
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{3, 4, 5, 6}
{3, 4, 5, 6} {3, 4, 5, 6}
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3 5
{3, 4, 5, 6, 7} {2, 3, 4, 5, 6}
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The Core of Constraint ComputationThe Core of Constraint Computation
Modeling– What should the variables/domains/constraints
be?Heuristic Search
– Quality vs. complexity trade-offInference/Propagation
– How much effort should be spent on inference?
Focus of 4C: Automating the process of constraint modeling and solution strategy configuration
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OutlineOutline
What is Constraint Computation?What does constraint computation have to
do with SCM?
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A Commercial RealityA Commercial Reality
First-tier software vendors embed CP technology in their SCM software
This is not to imply that SCM is a “solved”
problem
Nor that CP is (just) a matter of
engineering
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CP & SCMCP & SCM
The puzzle is actually a hard problem– NP-complete
Can apply the same technology to core SCM problems– Vehicle routing– Scheduling– Warehouse location
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Example: Vehicle RoutingExample: Vehicle Routing
Depot
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[10 20][15 15]
[10 20][25 20]
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Example: Vehicle RoutingExample: Vehicle Routing
Depot
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[10 20]
[10 20]
[20 20]
[10 10]
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SCM is DistributedSCM is Distributed
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Distributed Problem SolvingDistributed Problem Solving
SCM cannot be solved centrally– Problem size, authority, corporate structure
Distributed problem solving is key
– Sub-problems are still important (and hard!)
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SCM-related Research at 4CSCM-related Research at 4C
Scheduling & vehicle routingDistributed scheduling Negotiation & privacySoft constraints & preferences
Focus on reducing the cognitive load for using existing technology
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Research at 4C: Extending SCMResearch at 4C: Extending SCM
Concurrent engineering– Extend the supply chain to design phase
On-line configuration– Bring the individual into the supply chain
Dealing with uncertainty– The course of true SCM never did run smooth
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Take Home MessageTake Home Message
CP is a commercial reality in SCMInsight into the core of CP technology4C is pushing the bounds of CP
– Automation of hard parts of using CP– Application of CP to new problems
4C is interested is SCM– Application for on-going research– New opportunities
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Director: Professor Gene Freuder
E-mail: [email protected]
External Liaison Officer: Dr. James Little
Phone: +353-(0)21-4255410
E-mail: [email protected]
Post: 4C, UCC, Cork, Irelandwww.4c.ucc.ie
4C - Contact Information4C - Contact Information