The Resource Priorities tab page is used to decide which yard tasks should be serviced first. When a yard resource ([RTG](RTG.html), [top loader](TopLoader.html)) has several tasks in its queue (trucks waiting to dropoff or pickup containers), it uses these values to assign a score to each task. The highest scoring task is then serviced. This calculation is redone every time a task is finished so that any newly arriving tasks are also evaluated. Tab Page Details  A yard resource may have several trucks waiting on it at once. Some trucks may be waiting for containers to take to a ship; others may be dropping off containers from a ship. Some trucks may be transferring containers via the gate or the rail. The operation of the yard requires that some of these trucks receive service before others, such as giving priority to shipping operations. Therefore it isn't sensible to simply service trucks in the order they arrive. Rather, a decision needs to be made with respect to the priority of the truck's service request. FlexTerm handles yard priorities by assigning a score to each service task. The assigned yard resource services the highest scoring task, then re-evaluates all tasks currently in its queue, including any newcomers. The new highest scoring task is then serviced and so on. Scores are calculated by adding together the values (or scores) on this tab page for each task (or truck). Each score can be a positive or negative number, depending on your objectives. For instance, in the scoring list shown above, the highest priority is given to shipside operations, next to gateside operations, and lastly to internal yard operations by assigning decreasing positive scores to each. A negative score is given to the distance to travel in order to encourage the yard resource to save time by doing as many tasks in the same location as reasonable. Notice that a small positive weight is also given to the amount of time a truck has been waiting. In this way, trucks that otherwise have the same score are serviced in the order they arrived, plus trucks with lower priority tasks (like yard operations) that have been waiting a long time will eventually be serviced. The scoring options available are as follows: - Shipside Operation - The score is applied if the task is related to loading or unloading a container for a ship. - Gateside Operation - The score is applied if the task is related to a truck arriving via the gate. - Internal Yard Operation - The score is applied if the task is related to yard management operations, such as moving containers from one yard block to another. - Bay change - The score is applied if the yard resource must move to a different bay than it is currently on to service the task. - Distance to Travel - The score is multiplied by the number of meters (or feet, or inches, etc.) the yard resource has to travel to service the task. Thus, if a bay change is required, a closer bay is preferred. - Time Since Initial Dispatch - The score is multiplied by the number of minutes (or seconds, or hours, etc.) the truck has been working on its current task. This typically receives a small positive score to help trucks complete their tasks in a timely manner. - Time Since Arrival - The score is multiplied by the number of minutes (or seconds, or hours, etc.) the truck has been waiting for the yard resource. This typically receives a small positive score to help trucks complete their tasks in a timely manner. - Dig Number - The score is multiplied by the number of containers the yard resource must displace in order to service the task. This typically receives a negative score so that other simpler tasks can be completed first (and possibly free up the buried container in the process).聽 - Stacking Operation - The score is applied if the task is a stacking (or dropoff) task. - Truck Arrived - The score is applied once the truck has actually arrived at the block. All other scores are applied as soon as the truck has been dispatched to the block so that an idle RTG can move to the block in preparation for the arriving truck. However, a large score is applied once the truck arrives so that the RTG will service trucks at the block rather than being tied up waiting for a truck en route. Note: FlexTerm聽can actually have more than one resource priority聽strategy.聽 These resource strategies are stored under the label "resourcequeuestrategies" of the yard object. The value in the resource's label "queuestrategy" specify which strategy to use for the resource. The resource strategy can have custom code as well. The code needs to be under the treenode of the strategy with the name "custom" and tagged as Flexscript. In the custom code, parval(1) is container id, and parval(2) is the calculated priority score based on the weights specified in the tab.