Table of Contents
Agent Based Models of Supply Chains
PPT Slide
Program for the Study of Complex Systems at the University of Michigan
Overview
What are the features that make supply chains so problematic?
The Seven Habits of Highly Ineffective Supply Chains
These features may be stated more generally
These are all hallmarks of a complex adaptive system
What are some of the specific ways in which supply chains manifest characteristics of complex systems?
Supply Chains as Dynamical Systems: Structural Issues
Supply Chains as Dynamical Systems: Intrinsic Nonlinearities and Adaptivity
An Additional Problem: Data Analysis
Modeling of complex systems: Lightning discussion
Better approach: Direct emulation of the distributed agents in the system
Down side
The Model
The Supply Chain Hourglass
Entities
Some Agent Behaviors and Independent Variables
Operating Assumptions
PPIC Algorithm
Forecasting Methods
Typical Forecasting Methods
Results
Some quantities we study
Variation Amplification
Variation Amplification: Mechanisms
Variation Modification in Weighted Forecasting
Amplification: Raw Data
Variation Amplification in DASCh Orders at Each Level
Variation Amplification in Automotive Orders
Order Volatility, 1971-1995 (Anderson, Fine, and Parker, MIT, 1996)
Variation Modification in Weighted Forecasting: Theory
Confirmation of < ?(t)2> ? L2< ?(t)2> Site2 ? Site3 Variance
Confirmation of < ?(t)2> ? L2< ?(t)2> Site2 ? Site3 Variance
Confirmation of < ?(t)2> ? L2< ?(t)2>/f2 Site 2 ? Site3 Variance
Variation Modification in Pass-Through Forecasting
Pass-Through Forecast Fit 183.7 + 3.1*(ConsVar + N2*L2 + N3*L3)
Implications of Variation Amplification
Variation Modification: Correlation Time-Delay Plots detect Variation Correlation (One-Step Time-Delay Plots)
Variation Amplification & Correlation in Real Data
Linear correlation due to linear feedback generated by the supply chain--Eg. Orders from site 2 to site 3
Implications of Variation Correlation
Variation Persistence
Variation Persistence
Trade-Off in Forecast Window Length
Implications of Variation Persistence
A nonlinear phenomenon: Generation of inventory oscillations Even with constant supply and demand, internal dynamics of the supply chain can generate oscillations.
Oscillations: Description
The DASCh Oscillator (Phenomena)
Oscillation Generation
Characteristics of the Inventory Oscillator
The DASCh Oscillator (Mechanism)
Geometrical interpretation
Implications for nonlinear dynamics
Implications of Oscillation Generation
Summary
Summary, cont.
Overarching conclusions
CEC Approach: Philosophy (1)
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