Glossary

The following definitions are of terms relating to SIMUL8, simulation, or industry sectors SIMUL8 is commonly used in.

A

Attributes

Attributes is a term used to describe the properties of a Work Item. In SIMUL8 we refer to attributes as LABELS.

B

Bitmap

A bitmap is an image file. Bitmaps have a file extension .BMP and can be created using Microsoft Paint or any other graphics program. The larger a bitmap the longer it takes windows to display it. For this reason, if you regard the speed of your simulation as important, try to keep bitmaps small. The size of bitmaps used for statics graphics (placed on the screen with the Graphics Palette) have no affect on speed.

Blocked Activity

An Activity is blocked when it cannot pass its current Work Item onto wherever it needs to go next.

Blocked Start Points

It is usually best to connect Start Points to Queues first, otherwise, if two Work Items arrive in quick succession, and the Activity you have routed them to cannot accept them (if it is busy) then the Work Item will be thrown away, and will not enter your simulation. Sometimes you might want this: if, for example, you want to simulate customers being lost because a phone system is busy. If you want to count the work-items being lost connect the work-entry point to a work-exit or queue. Set the Routing Out discipline from the work-entry point to priority. Make sure that the preferred route is listed first.

C

Cumulative Probability Data

Cumulative Probability Data is where the probabilities next to each sample value are the probability of this sample value PLUS the probability of all preceding sample values.

D

Distribution

A distribution is a statistical device that describes the natural variability that occurs in real life.

Dummy Activities

Sometimes it is useful for an Activity to control the flow of work between two Queues without actually holding the work for any time in the Activity. This is called a Zero Time or Dummy Activity as the step does not actually exist in the process. This is achieved by setting the Activity to take zero time by using a Fixed Distribution. However there can be issues with this approach. If the destination object of the Activity has no capacity limit then all the work in the source object will pass to the destination object immediately after it enters the source object. Also if the destination object has a capacity limit then 1 item of work will leave the source object before the destination object can accept it, and will wait in the Activity. Two options which avoid thesesituations: Wait till exit clear and Zero timing.

F

FMCG

Fast Moving Consumer Goods (e.g. Soap Powder, Prepacked Food)

K

KPI

Key performance indicator.

R

Routing

Routing lets you control the path taken by each individual work item through the simulation. You have an opportunity to control routing as work items enter and leave objects on the screen. Click the Routing In or Routing Out buttons in the Activity dialog box. Routing can be controlled at Activities and Conveyors but can also be controlled at other objects by using “invisible” Activities.

S

Synthetic Activities

An Activity that is used to simulation a piece of logic in the real situation but that cannot be “seen” in the real situation (it does not physically exist as a machine). Usually used to control routing in a simulation simulation. Their “timing” is usually set to FIXED 0.

T

Takt Time

Takt Time is a manufacturing term meaning the pace that production must take place to satisfy customer demand. For example, if 900 items are required to be produced every shift, and a shift has 7.5 production hours (450 minutes) then 900/450 tells us that 2 items must be produced every minute. Hence the Takt time is 0.5 minutes. This means that each step in the production process must produce an item every 0.5 minutes to satisfy demand. Use the Index with Groups function to recreate Takt Times.

Trying Steps

Trying steps are when SIMUL8 checks to see if, for example, an Activity can start work. If no work (or the appropriate Resources) the “try” will not be successful. Successful “trys” are always shown but you can switch off display of these test that do not succeed. There are often a great number of these in any simulation simulation.

V

VL

This is a short hard way we often use to describe Visual Logic.

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