DSES-6620 SIMULATION MODELING AND ANALYSIS
Spring 2002
Project Proposal – R. Sewersky
Summary: Select a module of a previously developed Supply Chain Simulation (developed in
TaylorED) and complete analysis to verify and validate it. Selection will be primarily based on
data availability to support validation.
Background: United Technologies Research Center (UTRC) has recently developed as series of
TaylorED simulation modules to simulate the US Navy helicopter components supply chain.
The chain includes:
 demand for components due to wear/fatigue and maintenance given certain levels of
operational flight activities
 repair or overhaul of these components in the Navy and Sikorsky shops
 replacement of certain parts by vendors or Sikorsky manufacturing
The scope of the entire system is too large to consider complete validation as a class project so a
small subset will be selected and the V&V done on it. There was also an early prototype that
considered cumulated demand levels, processing at component turnaround time in the shop and
component inventory levels (for which some V&V was already done) that will also be
considered. The specific V&V tasks to be performed will also be downselected based on data
availability and previous V&V that was done.
Verification Tasks: The following are a list of the Verification tasks to be considered for the
project. Final selection and development of a draft schedule will be completed once the model
subject is finalized.
 Check literature regarding standard commercial or military practices that define
simulation qualification or validation. Report on those found relevant and consider
their guidance.
 Develop logic diagrams for the previously developed module.
 Analyze sensitivity to input variable excursions and assess whether the simulated
response seems correct. Provide supporting graphs and descriptions.
 Review animation output for reasonableness.
 Trace execution at key steps using debugging tools.
Validation Tasks: The following are a list of the Validation tasks to be considered for the
project. Final selection and development of a draft schedule will be completed once the model
subject is finalized.
 Compare simulation outputs with any available analytical tools that can provide
comparable outputs. In this domain, a commercial tool called OPUS is available to
model supply chain performance statically given average demand levels and average
processing times and inventory levels. Other OR tools such as Queuing or Inventory
theory will also be considered.
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OPUS assumes demands are Poisson distributed. Characterize actual demand data for
suitability of this assumption or propose a better distribution match using StatFit.
Compare model output variability with variability of available real performance data.
Obtain updated recent Navy demand data and factory turnaround times and compare
to simulation outputs
Weekly milestones:
2/28 – Summary of applicable commercial/military standards.
3/7 – Data inventoried (additional data requested), Module selected, plan updated.
3/14 – Logic diagrams developed, animation output checked.
3/21 – Input variable sensitivity checked, key steps debugged.
3/28 – Input variable and TAT distributions fit checked.
4/4 – Comparison with analytical model completed.
4/11 – Comparison with recent demand and factory data, draft report.
4/18 – Final report
4/25 – Class presentation.