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Activity-Based Costing
Modeling with activity-based costing
The information that is stored in these attributes depends on whether the item is a cost accumu- lator or a resource, as described in the following table:
Item type
Cost accumulator
Resource
_cost attribute
The accumulated cost of the item
The cost per use of the resource
_rate attribute
The item’s waiting or storage cost (cost per time unit defined using the model’s global time unit)
The resource’s cost per time unit (defined using the model’s global time unit)
The attribute handling blocks in the Item library (Get, Set, and Equation(I)) can be used to read, set, or manipulate these attributes. In addition, two statistics blocks in the Item library (Cost By Item and Costs Stats) can be used to gather cost data.
Viewing Cost Data
You can use a Get block to read the _cost and _rate attributes of any item, then plot the data or use the attribute value to perform additional calculations. For example, you can use a Get block to read the _cost attribute of cost accumulators and connect the Get block’s _cost output con- nector to a Plotter Discrete Event to plot the accumulated cost of each item that passes through. This is shown in the model discussed in the following section.
Changing Cost Data
In most cases, it is sufficient to define the cost rates of the various cost drivers in a model and allow ExtendSim to automatically calculate and track costs. However, there may be times when you need to manipulate the cost values generated. The attribute handling blocks in the Item library (Get, Set, and Equation(I)) can be used to accomplish this.
Change Rate model
For example, suppose the cost rates of a resource vary throughout the day. During peak times the demand for the resource is high and the cost per time unit increases. This can be modeled using the Set block (Item library) and the Lookup Table block (Value library) to explicitly set
Discrete Event


































































































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