Extend is a simulation tool to create models quickly, with all the blocks you need and without even having to type an equation.

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1 - EXTEND
Extend is a simulation tool to create models
quickly, with all the blocks you need and without
even having to type an equation. You can use a
series of simple block definitions to describe
complex processes. Extend also provides an
equation editor so you can combine the function
of several blocks into one. You can even create
your own libraries of custom blocks for
specialized applications.
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1.1 What Extend Can Do
A full array of building blocks that allow you to
build models rapidly. A customizable graphical
interface showing the relationship in the system
you are modeling. The ability to adjust settings
while the simulation is running. Customizable
reports for presentation and in-depth
analysis. Full connectivity and interactivity
with other programs and networks.
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1.2 Continuous and Discrete Event
Extend libraries hold blocks that you can use to
create models. Classical simulation is generally
divided into continuous and discrete event. The
Generic and Electronics libraries are used for
continuous simulation. The discrete event
libraries (Discrete Event and Manufacturing) are
used for models that use queues, item-specific
attributes, and priorities. Other libraries are
included as well.
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2 RUNNING A MODEL
Model Composed of components (called blocks)
with connections between them Library
Repository of blocks (Turn on the PC ?) Start the
program Start ? Programs ? Extend6 ?
Extend6 Libraries are found by the Library menu
item. The most important parts of a model are the
blocks, the libraries where the blocks are
stored, the dialogs associated with each block,
the connectors on each block, and the connections
between the blocks.
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2.1 Blocks
A block specifies an action or a process. A block
in Extend is like a block in a block diagram. It
is used to represent a portion of the model. Some
blocks are a source of information, other modify
information as it passes through them.
Block
Input Connectors
Output Connectors
Dialog
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2.2 Libraries
The entire definition for a block is stored in
the library. When you include a block in a model,
a reference to the block information in the
library is included instead of copying actual
blocks to the model. When you open a model,
Extend automatically opens the needed libraries.
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2.3 Dialogs
Most blocks have a dialog associated with them.
You use dialogs to enter values and settings
before you run your simulations. To open a
blocks dialog, simply double-click on the
blocks icon. You can get more information about
the block by clicking on the Help button. To the
right of the Help button is a text entry box for
typing a block label. When you click on a button
while the simulation is running, it pauses, and,
after resuming, the block gets that changed
valued on the next step.
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2.4 Connectors and Connections
Most blocks in Extend have input and output
connectors (usually pre-defined) You use
connecting lines (connections) to hook blocks
together
Value Connectors Used to pass values
(information) Item Connectors Used to pass
entities (items)
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2.5 See Built-In Examples
Continuous Simulation ? Lake Pollution
Example Discrete Event ? Bank Line Example Open
? Examples ? Tutorials
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3 BUILDING A MODEL
New Model Open the libraries Add blocks to the
model Connect the right types of input with the
right types of output. The behavior of most
connectors is predefined. If the connection was
not made correctly, the line will show as a
dotted line instead as a solid line.
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4 CONTINUOUS AND DISCRETE EVENT MODELING
Continuous modeling is used to describe a smooth
flow of homogeneous values discrete event models
track individual and unique entities. In
continuous models values change based directly on
changes in time, and time changes in equal
increments. In discrete event models, simulate
time advances from one event to the next and it
is unlikely that the time between events will be
equal. You will often use blocks from different
libraries within the same model.
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4.1 Continuous Modeling
The blocks in the generic library are useful for
both quickly building continuous models, and for
performing specialized tasks when connected to
value connectors in discrete event models. If you
have connected an input and also enter a value
for that input in the dialog, the connectors
value always overrides the value in the dialog.
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4.2 Discrete Event Modeling
In discrete event blocks, an item connector
passes an item and all the information associated
with it to the next item connector. The Executive
block must be to the left of all other blocks.
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4.2.1 Items and Values
Items are individual entities that can have
unique properties as specified by their
attributes, priorities and values. Values provide
information about items and about model
conditions. Extend moves items in your model
only when an event occurs. Events are occurrences
and are controlled by the Executive block. Blocks
that do not generate events allow the blocks
after them to pull items during a single event.
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BIBLIOGRAPHY
- Extend v6 Users Guide