Page 11 - Continuous Process Modeling Quick Start Guide
P. 11

Introduction 7
How CP modeling compares to other methodologies
How CP modeling compares to other methodologies
The most important aspects of the three main modeling methodologies—continuous, discrete event, and discrete rate—are shown below.
Continuous Process
Discrete event
Discrete rate
System State Changes When
Time changes Event occurs
Event occurs
Models
Generic stuff
Identifiable things
Generic stuff
Attributes for Tracking
No Yes
Yes
Queued Order Method
N/A
FIFO, LIFO, Priority, or a custom order based on Item Attributes
FIFO, LIFO, or a custom order based on Flow Level Attributes
• Statechange.Modelsareeitherevent-basedortime-based.Continuousprocessmodelshave a fixed time step where time advances in equal increments and the model changes state at each time step. Discrete event and discrete rate models only change state when an event occurs.
• Whatismodeled.Continuousanddiscreteratemodelsbothmodelhomogeneous“stuff”, while discrete event models track individually identifiable “things”—entities or items.
• Tracking.Valuesincontinuousmodelsdonothaveattributes—propertiesthatallowavalue to be individually identified and manipulated. However, quantities of flow in discrete rate simulations can be assigned attributes, as can the entities in discrete event models.
• Ordermethod.Theorderinwhichthestuff(flow)indiscreteratemodelsorthethingsindis- crete event models leave a queue which is holding more than one quantity or thing. The stuff (values) in continuous models cannot be put into any order.
☞ For more detailed information, see the User Reference chapter titled Modeling Methodologies.
Where to get more information
The ExtendSim documentation, example models, and the video files and documents on the ExtendSim.com website provide comprehensive help.
Tutorial & Reference documents
In addition to the Quick Start Guides, there are three Tutorial & Reference documents that are included as eBooks in the Documents/ExtendSim/Documentation folder:
• ExtendSimDatabase.Thisinternalrelationaldatabaseprovidesmodeldeveloperswitha systematic way to manage information for the model and makes models scalable.
• AdvancedResourceManagement.ARMisasophisticatedarchitectureforsystematically dealing with multiple types of resources and a model’s complex resource requirements.
• Reliability.Graphicallycaptureandvalidatecomplexavailabilitybehavior.Determinewhen scheduled and unscheduled downs occur for individual resources and what impact that has on the availability of the system as a whole.


































































































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