Introducing Simio Version 10.181 – December 2018

States and Functions for Inventory Element

The states for the Inventory element include:
QuantityInStock - The current quantity of material present in the inventory.
AllocationQueue - Accesses the inventory’s queue of material consumption requests.

The functions for the Inventory element include:
AverageQuantityInStock - Returns the average quantity of material present in the inventory during the simulation run.
MinimumQuantityInStock - Returns the minimum quantity of material present in the inventory during the simulation run.
MaximumQuantityInStock - Returns the maximum quantity of material present in the inventory during the simulation run.
QuantityConsumed - Returns the total quantity of material removed from the inventory during the simulation run.
QuantityProduced - Returns the total quantity of material added to the inventory during the simulation run.
QuantityReserved - Returns the current quantity of material from the inventory that is reserved. QuantityReserved (owner) - Returns the current quantity of material from the inventory that is reserved for use by a specified owner object.
QuantityBackordered - Returns the current quantity of material required to satisfy all material consumption requests waiting in the inventory’s allocation queue.
AverageQuantityBackordered - Returns the inventory’s average quantity backordered during the
simulation run.
MinimumQuantityBackordered - Returns the inventory’s minimum quantity backordered during the
simulation run.
MaximumQuantityBackordered - Returns the inventory’s maximum quantity backordered during the
simulation run.
UsageCostCharged - Returns the total cost that has been charged to consumers of material from the inventory.

Material Element Enhancements

The Material element has been enhanced to include the Location Based Inventory property (default set to ‘False’). When the material is location based, the Initial Quantities and Allocation Ranking Rule will be specified on the associated Inventory element.

New Material Element Functions

With the Material element enhancements, we have added the following new functions for materials: Inventory (site) - Returns a reference to the inventory holding this material at the specified site (a fixed object). If there is no such inventory defined, then the Nothing keyword is returned.
QuantityBackordered - Returns the current quantity of material required to satisfy all material consumption requests waiting in any allocation queues.
AverageQuantityBackordered - Returns the material’s average quantity backordered during the
simulation run.
MinimumQuantityBackordered - Returns the material’s minimum quantity backordered during the
simulation run.
MaximumQuantityBackordered - Returns the material’s maximum quantity backordered during the
simulation run.
UsageCostCharged – Returns the total cost that has been charged to consumers of the material.
** NOTE: The MaterialCostCharged function is now deprecated, use the UsageCostCharged function instead.

Fixed Object Function Added

When a fixed object, such as a Server, Combiner, Separator or TransferNode, is specified as the Site Object Name of an Inventory element, the function Inventory (material) can be used.
Inventory (material) – Returns a reference to the inventory holding the specified material at this fixed object. If there is no such inventory defined, then the Nothing keyword is returned.

Consume, Produce, Reserve, UnReserve and Route Step Enhancements

The Consume, Produce, Reserve, UnReserve and Route steps now include an Inventory Site Type
property which can be specified as ‘None’ (default), ‘AssociatedObject’, ‘ParentObject’ or
‘SpecificObject’. Additionally, the Site Object Name property will then be visible if the Inventory Site Type
is ‘SpecificObject’. This allows these steps to then work with the Inventory element features.

If consuming, producing, reserving or unreserving a single material that is location-based inventory, then Simio will look up the Inventory element holding the specified material at the specified inventory site. If producing a bill of materials, then Simio will look up the inventory elements holding the component materials at the specified inventory site. This holds true for routing with required materials as well.

Standard Library Enhancements - Server, Combiner, Separator and TransferNode

The Server, Combiner, Separator objects have been modified to have Inventory Site Type and Site Object Name properties within the Task Sequences, Required Materials section of properties. This will allow users to specify, on a task basis, the inventory site area (if any) from which to consume or produce materials.

Additionally, the TransferNode object has been enhanced to allow required materials before routing out to include material that is location-based inventory.

Material Usage Log Enhancement

If logging material consumption and production, then the Material Usage Log now includes a new Site Id
field and the existing Stock Level field will now be the site location quantity in stock.

Resource Usage Log / Task Log Enhancement

We have added two properties to the Custom Column fields within the Resource Usage Log and the Task Log. The ‘Add Column’ button on the Log ribbon is used to add custom columns to the logs. This is typically done to provide the user with ‘Additional Details’ information on a tooltip or to categorize the resources or tasks. However, there are some instances when the extra column is used to provide information on the Gantt (border color, for example) but the user may not wish to have it shown on the hover tooltip and/or categorization fields dropdowns. The Show in Gantt Tooltips and Show in Gantt Dropdowns properties have been added to allow the user to turn off (‘False’) the display of the custom column in various places.

OptQuest – Minimum Replications

Within Simio experiments using OptQuest, users can now specify the minimum replications (Min Replications property) to 1. Previously, this value was required to be 5 or more.

Ability to View Product Version for Model

We have added the ability to view the product version and date with which the model was saved. Users can right click on the Project Name within the Navigation window to see the Project Properties. The Date Saved and Saved In Version fields are now available, as seen below in red. This was a user requested feature.

Right-Click – Export View To

We have added a new right-click option on the table areas (tables, experiment, etc.) that allows users to export the table view to several different sources, such as Excel, CSV, PDF, Html and Word
.

Material and Inventory – Partial Allocation

For a Material element, there is now an Allow Partial Allocation If property that is a default optional condition indicating whether an entity may immediately consume only a portion of its requested quantity if the full quantity is not available. If the condition evaluates to true, the entity will consume the partial amount, but will still wait until the entire quantity fulfilled before moving from Consume step.

For an Inventory element, we also added an Allow Partial Allocation If property that is an optional condition indicating whether an entity may immediately consume only a portion of its requested quantity if the full quantity is not available. If specified, then this condition will override the Allow Partial Allocation If on the Material element associated with the inventory.

Inventory Replenishment Framework

The framework that is now available in Simio to model inventory replenishment is illustrated in this video.

Inventory Position

The inventory position is a key input typically used in inventory replenishment decision making. It is equal to inventory-on-hand plus inventory-on-order minus backorders and any other commitments.

Continuous or Periodic Inventory Review

These terms refer to the frequency of inventory review to determine when orders must be placed for replenishment.

A continuous inventory review keeps a constant track of the inventory position; as soon as it falls below a pre-determined level (the reorder point), a replenishment order is placed. Tracking inventory levels in real-time is typically more expensive to administer but allows for a lower level of safety stock, as the only uncertainty is the magnitude of demand during the delivery period.

Alternatively, a periodic inventory review evaluates the inventory position at discrete points in time to determine if a replenishment order needs to be placed. Replenishment decisions can be made only at those points. The time between two review points is called the review period. A periodic review system is cheaper to administer compared to continuous review since inventory counts take place only at fixed times, but a higher level of safety stock is typically required to buffer against a longer period of uncertainty in demand.

Replenishment Policies

At the time of an inventory review, a decision strategy often referred to as the replenishment policy is used to determine whether replenishment is required and, if so, then by how much.
Some commonly used replenishment policies:

Min/Max Replenishment Policy
This policy is sometimes referred to as the (s, S) policy where s is the reorder point, the ‘Min’, and S is the order-up-to level, the ‘Max’. When the inventory position falls to or below the reorder point, s, then replenishment is required to bring the inventory position to the order-up-to level, S. In other words, if the inventory position is y, and y ≤ s, then a replenishment order of size S−y is required.

Figures 1 & 2 illustrate the Min/Max replenishment policy using either continuous or periodic inventory review.
Figure 1 – Continuous Review Min/Max Replenishment Policy

Figure 2 – Periodic Review Min/Max Replenishment Policy

Order-Up-To Replenishment Policy
This policy is sometimes referred to as the base-stock policy or “one-for-one” policy. When the inventory position decreases below the order-up-to level, S, then replenishment is required so as to bring the inventory position back to the order-up-to level. In other words, if the inventory position is y, and y < S, then a replenishment order of size S – y is required.

Figures 3 & 4 illustrate the Order-Up-To replenishment policy using either continuous or periodic inventory review.

Figure 3 - Continuous Review Order-Up-To Replenishment Policy
Figure 4 - Periodic Review Order-Up-To Replenishment Policy

Reorder Point/Reorder Qty Replenishment Policy
This policy is sometimes referred to as the (s, nQ) policy where s is the reorder point and Q is a fixed reorder quantity (a fixed lot size). When the inventory position falls to or below the reorder point, s, then replenishment is required to bring the inventory position just above s. The size of the replenishment order is a multiple of the reorder quantity, Q. In other words, if the inventory position is y, and y ≤ s, then a replenishment order of size nQ is required, where n is the smallest integer such that y + nQ > s.
Figures 5 & 6 illustrate the Reorder Point/Reorder Qty replenishment policy using either continuous or periodic inventory review.

Figure 6 - Periodic Review Reorder Point/Reorder Qty Replenishment Policy

Inventory Element – Replenishment Features

Within the Inventory element, we have added multiple properties to handle inventory replenishment, including Review Period, Replenishment Policy and On Replenishment Order Process. The Review Period determines the frequency of inventory review to determine whether a replenishment order is required.
This can be ‘None’, ‘Continuous’ or ‘Timer’ (periodic as discussed above). The Replenishment Policy
property can be specified as ‘None’, ‘Custom Reorder Condition’, ‘Min/Max’, ‘Order-Up-To’ or ‘Reorder Point/Reorder Qty’. Finally, an On Replenishment Order Process property can be executed to handle an inventory replenishment order. The initiation of this process automatically increments the inventory’s quantity on order. The created token’s material order detail reference (new) will provide the detail of the order replenishment.

Material and Inventory Elements – QuantityOnOrder state

For both the Material and Inventory elements, we have added a QuantityOnOrder state variable that returns the quantity of the material that has been ordered to replenish inventory in the system but has not yet been received.

If a material is not location-based inventory, this value will return 0. Otherwise, it is automatically assigned the value of the total aggregate quantity on order across all inventory sites and is not user- assignable. The inventory’s QuantityOnOrder state may also be assigned using the Assign step.

Inventory Element – InventoryPosition function

A new InventoryPosition function has been added for Inventory elements that is equal to the inventory’s quantity in stock plus quantity on order minus quantity backordered minus quantity reserved (excluding reserved units already backordered).

Consume Step – On Consumed Process
The Consume step now includes an option process to be executed when material is consumed. The created token's material order detail reference will provide the detail of the material consumption. This process will be executed any time a quantity of material is consumed; either a full or partial allocation.

Produce Step – Record As Order Received If Property
The Produce step now includes a Record As Order Received Condition property which, if ‘True’ and the material is location-based inventory, then the inventory’s quantity on order is automatically decremented by either the produced quantity or to zero, the latter if the produced quantity is greater than the quantity on order.

Token Function Enhancements

The following new functions will be provided by a process token:
MaterialOrderDetail - Returns a reference to the material order detail associated with the token, if applicable.
MaterialOrderDetail.Material - Reference to the material.
MaterialOrderDetail.SourceInventory - Reference to the inventory that is the source of the material. MaterialOrderDetail.SourceSiteObject - Reference to the inventory site object that is the source of the material.