The Arrival Patterns tab page is used to establish the days and hours in which trucks (and containers) typically arrive at the gate. Arrival patterns, or distributions, are specified for a week-long period. Tab Page Details  Distribution Selection - This drop-down box selects the arrival pattern that you are currently viewing/editing. By default there is only one arrival pattern named "Pattern1." New Pattern - Click this button to add a new distribution to the set of distributions. Additional distributions are useful for describing the pattern of specific containers (indicated by a unique [container type](Container_Types.html)). Duplicate Pattern - Click this button to add a new distribution to the set of distributions. The new distribution is a copy of the currently selected distribution. Delete Pattern - Click this button to delete the currently selected distribution from the set of distributions. <a name="DwelltimeVariabilityDef">Dwelltime Variability</a><a name="DwelltimeVariabilityDef">- This value, given in hours, is used to provide flexibility in the dwell time of containers so that truck arrivals can match the arrival pattern, yet still move containers in an acceptable time frame. </a>More details are given in the section of [Dwelltime Variability](#DwelltimeVariability). <a name="DualTransaction">Dual Transaction %</a><a name="DualTransaction"> - This value is the percent of trucks dropping off a container that will also pickup a container.</a> <a name="DualTransaction">Entry Chassis Transaction %</a><a name="DualTransaction">聽 - This value is the percent of trucks picking up a container that will first pickup a chassis (before a grounded pickup) or dropoff a chassis (before a wheeled pickup) prior to picking up a container. The model should include both a </a>[chassis pool](ChassisPool.html) and a [wheeled block](WheeledBlock.html). Exit Chassis Transaction %聽 - This value is the percent of trucks dropping off a container that will聽pickup a chassis (after a wheeled dropoff) or dropoff a chassis (after a grounded dropoff) prior to exiting the yard. The model should include both a [chassis pool](ChassisPool.html) and a [wheeled block](WheeledBlock.html). Total - This value is the total number of containers as defined by the arrival pattern. This number can be changed by raising or lowering the pattern bars by clicking in the graph to change the number of containers for a given hour. Scale - You can scale the entire pattern or certain days based on a percentage or a value using聽this button. The pattern will be used for the distribution of trucks throughout the week, but the actual number of trucks will be determined by the values in the Arrivals table. <a name="Copy">Copy</a><a name="Copy"> - Click this button to copy the arrival pattern of one day to that of another. Select the day you want to copy from in the first drop-down box and the day you want to copy to in the second drop-down box. Then press "Copy" and the pattern will be replicated. This is useful if several days of the week have the same pattern.</a> <a class="calibre7" name="ArrivalPatternView">Arrival Pattern View</a> <a name="ArrivalPatternView"></a> <a name="ArrivalPatternView">The arrival pattern view shows a bar graph of the weekly schedule for the gate. The vertical axis represents the number of containers. Please note that this is not the number of trucks as some trucks will perform two transactions thus the truck arrivals may be less than the total number of containers picked and dropped.The horizontal axis represents time beginning on Monday and ending on Sunday.</a> <a name="ArrivalPatternView">At the top of this view, you can see the total number of containers聽defined by the arrival pattern. By default, the total value is set at 10,000 containers per week. You can scale the arrival pattern based on the entire week (All Days) or based on specific days of the week. In addition, you can scale based on a total number or a percentage of the current total for the week or a specific day. When you have selected and input the appropriate parameters, press the scale button. The relative heights of the verticle bars will remain the same, but the numbers on the vertical axis will change. This is useful as it gives you the indication of the actually number of gate transactions if the pattern is scaled by the total number of transactions in a week. </a> <a name="ArrivalPatternView">The total values does not determine how many containers (and trucks) will </a><a name="ArrivalPatternView">actually</a><a name="ArrivalPatternView">arrive during the week. Rather, it indicates that </a><a name="ArrivalPatternView">if</a><a name="ArrivalPatternView">10,000 containers were to arrive during the week, this is how they would be distributed. You may find it easier to set the pattern聽if you scale to the actual number of containers you typically receive. Keep in mind that round numbers are generally easier to work with. </a> <a name="ArrivalPatternView">Each bar of the graph represents one hour of time and the height of that bar represents how many containers will arrive at the gate during that hour. You can adjust these bars by clicking and dragging on the pattern. Click below the x-axis (where the days of the week are displayed) to set no trucks to arrive during that hour.</a> <a class="calibre7" name="ArrivalPatternView">Arrival Pattern Runtime View</a> <a name="ArrivalPatternView"></a> <a name="ArrivalPatternView"> While the model is running, you can track the current activities of the gate in the arrival pattern view. At the beginning of each week, red bars are drawn over the pattern to show the </a><a name="ArrivalPatternView">actual </a><a name="ArrivalPatternView">number of containers scheduled for that hour (both pickup and dropoff). During runtime, a thin black line appears on the view and moves to the right as time progresses. This line shows the current day and hour of the model. As the black hour line crosses a red container line, the red line begins to shrink. This indicates that some containers have already been moved and the remaining red line is the number of containers yet to be moved.</a> <a class="calibre7" name="DwelltimeVariability">Dwelltime Variability</a> <a name="DwelltimeVariability">The </a>[dwelltime variability](#DwelltimeVariabilityDef) is used to provide flexibility in the dwell time of containers so that truck arrivals can match the arrival pattern yet still move containers in an acceptable time frame. The value is the number of hours that FlexTerm can add or subtract to a container's dwell time when assigning the time that the container will be picked up or dropped off via the gate. The algorithm for a pickup works as follows: 1. A container is dropped off in the yard from a ship, or from an abstracted source, and is destined for the gate. The container's dwell time is calculated based on the value provided in the [Container Types window](#DwelltimeVariabilityDef). 2. FlexTerm looks at the end of the dwell time and schedules the pickup time of the container by the following situations: 1. If the gate is open at that time, FlexTerm looks at a window the size of the dwelltime variability (both to the left and right) to decide where to slate the container - trying to match the arrival pattern as closely as possible. 2. If the gate is closed at that time, FlexTerm looks for the closest hour when the gate is open, which may be earlier or later and may even be a day or two later. It then looks at a window the size of the dwelltime variability (in both directions) to decide where to slate the container so the arrival pattern is met. The algorithm for a dropoff works similarly except that FlexTerm calculates the dwell time and dropoff time backwards from the pickup time. As an example, consider the following arrival pattern. The gate is open from 8 a.m. to 5 p.m. every day and is closed on Saturday and Sunday. The dwelltime variability is given as 10 hours. A container arrives from a ship on Tuesday at 3 p.m. Case 1. The container has a 24-hour dwelltime, therefore the container should leave at 3 p.m. on Wednesday. The gate is open at this time (situation 'A' above). FlexTerm now decides what pickup hour will best meet the arrival pattern. FlexTerm can schedule the pickup up to 10 hours before (5 a.m.) or 10 hours later (1 a.m.). Of course, the hours when the gate is closed aren't really considered. In this case, the container may be assigned an exit time between 8 a.m. and 5 p.m. on Wednesday. Case 2. The container has a 30-hour dwelltime, therefore the container should leave at 9 p.m. on Wednesday. The gate is closed at this time (situation 'B' above). FlexTerm looks for the closest hour when the gate is open. It considers an earlier time (5 p.m. Wednesday) and a later time (8 a.m. Thursday). 5 p.m. on Wednesday is closer. FlexTerm now looks 10 hours to the left of this time (7 a.m.) and 10 hours to the right of this time (3 a.m.). Again, the hours when the gate is closed aren't really considered. In this case, the container may be assigned an exit time between 8 a.m. and 5 p.m. on Wednesday. Case 3. The container has a 40-hour dwelltime, therefore the container should leave at 7 a.m. on Thursday. The gate is closed at this time (situation 'B' above). FlexTerm looks for the closest hour when the gate is open, which may be at 5 p.m. on Wednesday or 8 a.m. on Thursday. Now 8 a.m. on Thursday is closer. Next, the 10 hour dwelltime variability is considered with a window from 10 p.m. Wednesday to 6 p.m. Thursday, with the gate closure hours not considered. In this case, the container may be assigned an exit time between 8 a.m. and 5 p.m. on Thursday. The length of the dwelltime variability determines which factor is more important - the dwell time or the arrival pattern. A small or 0 dwelltime variability indicates that the dwelltime should be met with little regard to the arrival pattern. A large dwelltime variability indicates that the arrival pattern should be met with significant flexibility in the dwell time. As an example of this,聽consider the arrival pattern shown in the pictures above. The gate is open from 8 a.m. to 5 p.m. every day and is closed on Saturday and Sunday. A ship drops off 1,000 containers at 2 p.m. on Saturday each with a 14 hour dwelltime. The containers should leave at 4 a.m. on Sunday, but the gate is closed. FlexTerm finds the closest hour the gate is open, which is 8 a.m. Monday morning. If the dwelltime variability is small, say 2 hours, all of those containers will be slated to exit within the first 2 hours of Monday's traffic. This will deviate from the arrival pattern, but accommodate the dwelltime as closely as possible. If the dwelltime variability is large, say 30 hours, those containers will be spread out across Monday and even into Tuesday. This will accommodate the arrival pattern, but cause a large fluctuation in the dwell times.