Step-by-step: Analyze

Bryony Coombs

December 21, 2022 23:33

Getting Started with Analyze

A. Intro to Analyze Page

From the Explore page, the user can select any solution (or dot) and open up a new Analyze page. On the Analyze page, users can review the schedule’s Gantt chart, the associated 4D simulation, and the project analytics. Each dot opens up into its own Analyze page and is independent from the other dots.

B. Analyze Page Interface

To enter the Analyze page for a specific schedule, select the dot on the Explore page, and click “Analyze Solution."

Click on the ALICE logo to go back to the Project List
Click on to open Plan List
Click on the project name to go back to the Explore Page
4D View Simulation Timeline
Click on the Help button to search articles in the ALICE knowledge library
Export the 4D animation
4D animation View
Gantt chart

C. Gantt Chart

The Gantt chart is a bar chart that illustrates the project schedule. At a minimum, it includes a list of all operations, its start and end dates, and a bar chart with time on the x-axis.

C.1 Gantt Chart Interface

On the Gantt chart, users can review or control the following:

View: can toggle between the following views: Gantt & 4D, Gantt Only, and Analytics & 4D
WBS: can toggle between the following structures: Sorted List, Recipe, Subcontractor, Level, and Custom WBS
Filter Start Time and Finish Time: can focus the Gantt chart and 4D view to a specific timeline
Filter: Filter the Gantt chart and 4D view by project resources
Enable Criticality: Enable viewing the Show Predecessor + Resource Arrows, Critical Tasks and Longest Path.
Activate this to start Manage for this schedule
Export to CSV or P6 XML
Zoom In & Out to expand or contract the timeline
Task ID
Task: Description of task
Start Date and Finish Date

C.2 View

Users can switch between the following views:

Analytics & 4D

This provides you with a view of the data behind resource utilization. From the analytics view you can filter for crews, workforce, equipment, materials, and cost overtime. All of the analytics data can be exported to CSV.
Analytics view is recommended for looking at resource utilization and can help you increase utilization of resources and reduce downtime

Gantt & 4D

This view enables you to view the Gantt and the 4D view. Utilize all of your filte and click 4D to filter your 4D view as well
Custom Gantt WBS format here will drive the P6 export WBS format

Gantt Only

This view is recommended for deeper schedule review in Gant format. You can see the gantt in full screen and see all relationship details
Custom Gantt WBS format here will drive the P6 export WBS format

C.3 WBS (Work Breakdown Structure)

ALICE allows users to group the Gantt chart with the following options:

Sorted List: sorted in ascending order based on the task timeline (i.e. earliest tasks first)
Recipe: all tasks are grouped by Recipe, then by Operation
Subcontractor: all tasks are grouped by Subcontractor, then by Level, then by Element
Level: all tasks are grouped by Level
Custom WBS: user can customize the grouping

Note: If milestones exist, then all milestones are grouped together at the top of the list. This is for all WBS settings.

Tip: Hold down the “alt” key on the keyboard and select thebutton at the parent level hierarchy to collapse the entire Gantt chart.

Custom WBS

With Custom WBS,users can sort the Gantt chart by any combination of default parameters, custom parameters that were created on the Plan page, or BIM parameters that were imported on the Plan page.

The user will add the hierarchy of the WBS in the order of the desired grouping.

Example: In the image below, the user wants to group the WBS in 3 levels as follows: “element_alice_section,” followed by “element_alice_type,” and then followed by “WBS_Level_3.” There is no limit to how many hierarchical levels within the WBS.

A sample of the Gantt chart output using the custom WBS is shown above:

C.4 Start Time and Finish Time

With Start Time and Finish Time,users can filter and isolate a specific timeline on the Gantt chart for closer review.

C.5 Filters

Text Filter

ALICE TextFilters allow users to filter out the Gantt chart in the following ways:

Crew
Criticality
Element
Equipment
Group
Material
Operation
Recipe

Note: Only one setting of each type can be used to filter the Gantt chart.

Tip: To select multiple criteria to create an “and” filter, the user can use this sample syntax in the filter bar: “crew:/C_Carpenter|C_Concrete|Facade|Fire/”.

4D Filter

The 4D View can be filtered by checking the box next to the Text Filter bar. Once the toggle is checked on for the 4D Filter, the 4D View will only display the items in the filter.

C.6 Driving Constraints

“Driving Constraint” shows the main driver of the selected operation. The driving constraint can be either due to precedence logic or resource availability. This is unique to ALICE as legacy scheduling tools only showcase predecessors without differentiating between precedence logic or resource logic.

To see the “Driving Constraint”, click on the task bar on the Gantt chart.

The precedence logic driving constraint shows the list of the driving operations with the relationship type and the associated lag hours.

The resource driving constraint shows the list of previous tasks using the same resource.

D Criticality

D.1 Overview of Criticality

What is Criticality?

In general, when it comes to project planning/scheduling, criticality refers to the “importance” of some activities over others.

This “importance” can be defined in many ways, such as:

Importance in terms of effect on delaying the project: This is mainly what the Critical Path Method (CPM) focuses on, and is the main component of what ALICE focuses on.

Example: In the image above, Task A is more Critical than Task B below because delaying Task A will extend the project duration, whereas any delay that is less than 10 days for Task B will not affect project duration.

Importance in terms of increasing project risk: This is not considered with CPM, and is currently addressed using techniques like Monte Carlo Simulations.

Example: In the image above, Task C is more Critical than Task B in the case below because even though both have the same amount of Slack time before delaying the next activity, delaying Task C affects many more activities than delaying B would. Therefore, the project risk associated with delaying C is higher than that of delaying B.

Importance in terms of value added to the customer: Although traditional CPM can sometimes represent this using Milestone constraints, this is usually left to the Project Team to assess and analyze during look-ahead planning sessions.

Example: In the image above, according to CPM, “Landscaping Finishes” may be more “critical.” However, if we take into account where the customer finds value, “HVAC final balance” may be more critical as it allows sooner operation of the building despite the project not being fully complete.

While there are plans to have ALICE directly address all three aspects mentioned above of Criticality, this document focuses mostly on the first aspect.

The other two can be indirectly addressed using Manage reschedule/re-sequence, Milestone Constraints, and the 4D visualization capabilities of ALICE.

Overview of Current Functionality

One of the fundamental differences between the traditional CPM scheduling workflow and the ALICE planning workflow is the following:

In the CPM workflow, the resource and precedence rules are applied as the schedule is created and they become inseparable from the resulting schedule.
In the ALICE workflow, the resource and precedence rules are encoded into the plan, and then they are repeatedly reapplied as ALICE generates multiple scheduling options.

This allows ALICE to maintain some level of flexibility with resource allocation when solutions are produced.

Example: Let’s consider this simple scenario where interior finishes need to be installed in 5 different rooms (A,B,C,D,E). The rooms are independent (no sequence constraints) and need 10 days of work each to be finished. Because of space limitations, we cannot fit more than 1 crew inside the same room in order to speed up the work in that room. We only have 2 Crews available for this project. The typical solution to this project looks like the image below.

Two crews work concurrently for the first 20 days followed by one of the crews working alone to finish the remaining room.

When this same problem is solved using the CPM approach, the planner/scheduler has to assume the logic relationships between the tasks above to build a working CPM schedule.

However, we notice that this can be done in many ways:

Option 1:

Option 2:

Option 3:

Etc…

The planner has to be careful with which option to proceed with as each option will result in a different “Critical Path.” In this approach, the flexibility of re-allocating crews in the case of delays is lost. However, sooner or later, the planner will have to move to that second stage where the flow of resources is determined in order to practically execute the project.

The “Enable Criticality” feature in ALICE allows the planner to move to that “Resource Instantiation” stage while being able to retain the original plan in case of any delays by following the resource logic (or the resource arrows).

This provides the planner with the “best of both worlds”: being able to use Criticality Metrics whilst also being able to retain the original plan in case of delays and re-sequencing.

This is called constraint conversion or “resource instantiation”, because instead of just working with crew availability, we now know specifically how each crew instance is flowing through the various areas of the project.

D.2 Enable Criticality Interface

“Enable Criticality” gives access to the Critically Tools, including:

Show Arrows
Show Critical Tasks
Show Critical Path
Relationship Details

Click on the “Enable Criticality” to enable the Critically Tools.

D.3 Show Arrows

The “Show Arrows” toggle will turn on the relationship arrows on the Gantt chart. The arrows show the flow of precedence logic and resources across the project. There are three types of relationship arrows in ALICE: Precedence Arrow, Resource Arrow, and Critical Path Arrow.

Precedence Arrows are thepurple colored arrows. Hover the mouse on the arrow to review the driving task information. Users can see the precedence activity name, the element or group name, and the relationship type
Resource Arrows are the gray colored arrows. Hover the mouse on the arrow to review the driving resource information. Users can see what resources are driving this activity and the previous tasks that are using the resources
Example: In the image below, qty 1 concrete crew and qty 1 concrete pump are traveling from Structural Foundations East to Structural Foundations West
Critical Path Arrows are the red colored arrows. Any logic link will turn red if the link is on the critical path and the critical path toggle is turned on

D.4 Critical Path and Critical Tasks

The critical path is the path that if delayed, and no re-sequencing occurs, will definitely delay the project. By selecting “Show Critical Path” and “Show Critical Tasks,” the users can visualize the Critical Path and Critical Tasks of the project. All critical activities will have colored hatches on the Gantt chart.

To see only the critical path or critical tasks on the Gantt Chart, go to Filter → Criticality → Critical Path / Tasks.

Difference Between Critical Path vs Critical Tasks

Not every task that has zero total slack / float (critical) is necessarily part of the critical path.

In P6, this distinction is avoided by simply saying “Critical” in filters rather than “Critical path,” but then you can also differentiate between “Zero Float” and “Longest Path.”

Here are two reference articles that explain in much greater detail the differences:

Example: In the two images below, the yellow colored boxes are the critical path and the blue colored boxes are the critical tasks.

For the critical path, the activities must be completed without delay or else the overall project will be delayed. Tasks P1a, P1b, and P1c all have zero float.
For the critical tasks, P2b has 4 days of float due to the calendar assigned to this task. The gray bar that precedes P2b indicates those are non-working times. So while P2b does have float, it also is a critical task that will affect the overall project duration if it is delayed.

D.5 Relationship Details and Slack (Float) Values

Under “Relationship Details,”users can review the full list of predecessors and successors, as well as the Free and Total Slack of the selected operation.

To see this information, click on the “Relationship Details” button on the bottom right corner.

In the “Relationship Details,” users can review:

Predecessors and Successors
Reason: whether it is a Precedence Driver or Resource Driver (if resource driver, the specific resource type will be noted)
Details: Relationship Type or Resource Driver Name (if resource driver, the resource quantity is noted)

Free and Total Slack

Free Slack: amount of time that a given task can be delayed without affecting any other task in the schedule
Total Slack: amount of time that a given task can be delayed without affecting the total project duration
The user can hover over the information icon to get more granular details.

If the activity names are orange colored,then these are critical activities.

Click “Select” on the right hand side of each activity to jump to that activity.

D.6 Known Limitations

Forward Pass & Backward Pass

In traditional CPM methodology. The Float (Slack) values for each activity are calculated by doing:

A Forward Pass: to determine the earliest possible start of every activity
A Backward Pass: to determine the latest possible start of every activity

Subtracting Earliest Start from Latest Start to determine the range of time through which the task can “Float” around in without delaying the project.

As of now, ALICE assumes that the user will be using the ALICE suggested dates and therefore uses those dates instead of doing a forward pass calculation.

For example: In the image below, while it is possible to start Task A 5 days sooner, resulting in 15 days of Total Float, ALICE will assume that you plan on executing the plan as-is and therefore report that you only have 10 days of “Slack” before you risk delaying the project.

If the forward pass was added, then the reported value would have been 15 days instead of 10, possibly misleading the project manager with regards to the buffer available.

Workforce Limit

The workforce limit constraint is currently not represented in Criticality, therefore if workforce limit is a key driver of the project, then users will have to rely on active drivers to explain sequencing.

E. 4D View

On the right hand side of the Analyze page, users can review the fully resource loaded 4D animation of the project.

Users can control the speed or timeline of the 4D simulation from the upper left hand side of the Analyze page by selecting from the dropdown menu with increments in: Hour, Day, Week, Month, Year and by Task.

E.1 Task Cards

Task Cards are located on the bottom part of the 4D animation

With Task Cards, users can review details of each operation, such as:

Resource name and quantity of resources used
Operation Name
Group / Element Name
Planned Start Date / Time and Planned Finish Date / Time
Duration in working hours

Click on the Task Card to highlight the operation on the Gantt Chart.

Similarly, you can use the 3D model to find or highlight the operations or task cards of certain 3D elements..

Select the 3D element → click the right mouse button → select “Show Task” from the dropdown menu

E.2 Settings

The 4D view settings are located at the bottom of the viewer. It includes the following:

Orbit: To rotate the 3D view
Pan: To move the 3D view
Settings: To change the Configuration, Navigation, Appearance,and Environment settings of the Plan module

F. Export CSV and P6 XML

ALICE allows users to export the project schedule and all metadata in CSV formatand P6 XML format.

The export functions are located in the top right hand side of the Gantt chart:

F.1 Export to CSV

Before generating the CSV file, the user is allowed to select (check / uncheck) the information required in the export. With “Export to CSV,” users can export:

Task Names: Always included in the export
Task IDs: Always included in the export
Start and Finish Dates: Always included in the export
Resources: Crew, Subcontractor, Equipment, Material, Rates
Recipes: Recipe Name, Operation, Element, Element ID
BIM: BIM Elements
Scheduling: Predecessors, Latest Start / End, Critical Path / Tasks, Free / Total Slack
Custom Properties: Custom parameters and imported BIM parameters
Costs: Total, Direct, and Idle costs of all resources

F.2 Export to P6 XML

Customizing Export Settings

The P6 XML export may be used for various purposes and different organizations may have different preferences on how much in what format is the schedule metadata exported. Fortunately ALICE allows for detailed customization of the P6 export. Below is a summary of the export settings available.

Resource Logic:

Selecting this functionality will:

Export All of the resource logic with the specific flow for each resource (if criticality is enabled)
Export the active drivers as resource logic with less detail w.r.t flow of each resource (if criticality is not enabled)

Turning this functionality off will:

only export support logic and disregard any resource logic in the P6 XML

Custom Properties:

When turned on, the custom properties assigned to each work element will be exported and assigned to all Activities that involve this work element.

You can chose between two formats in which they come in to P6 depending on your preference:

As Activity Codes

The property name is the activity code name
The property value is the activity code description
Choose this when you want to avoid Enterprise metadata and want to enclose all metadata in the project itself

As P6 UDFs

The property name is the UDF name
The property value is the UDF value
Choose this when you don’t mind using Enterprise metadata and want to avoid activity codes with long lists of values

Resource Assignments:

When turned on, resource information is exported and assigned to each task. You can choose the format in which this information is exported:

As Activity Codes

can be used for grouping and sorting
cannot be used for resource leveling or resource usage plots
properties remain enclosed in the project (not a global enterprise property)

As Resources

can be used for grouping and sorting
can also be used for resource leveling and resource usage plots
results in the creation of enterprise resources grouped under ALICE headers (ex: ALICE Labor, ALICE nonlabor, ALICE materials)

Costs:

When selected, your P6 XML export will be cost loaded. Only direct costs will be added as P6 does not support idle cost calculations.

You may chose the format in which costs are loaded:

As Expenses

Provides a cost loaded schedule where each cost is a task expense
Expenses are separated by category (labor, equipment, material)
Is more tedious to manage in P6
but does not require the creation/use of enterprise resources

From Resources

Provides a cost loaded schedule by assigning costs to the resources used
Only works when resources are exported as resources
Is easier to Manage in P7
but required the creation/use of enterprise resources

Milestones:

When selected, this option allows for the export of ALICE milestones to P6 with the relevant task logic.

G. Analytics

G.1 Intro to Analytics

The user can review the analytics related to the schedule by selecting “Analytics & 4D” in the View dropdown menu.

The table below provides a general overview of the available analytics graphs in ALICE as well as their basic properties:

Available Graph	Cumulative vs Daily	Affected by Filters
Crew Utilization	Daily	By Crew Filters
Workforce Utilization	Daily	No
Material Consumption	Daily (for Reusable) Cumulative (for Consumable)	By Material Filters
Equipment Utilization	Daily	By Equipment Filters
Crane Utilization	Daily	No
Cost Over Time	Cumulative	No

Cumulative vs Daily: In each of the graphs, the x-axis represents time. For the resource utilization and consumption graphs, the y-axis represents resource quantity. These quantities are either for their daily usage or for their cumulative consumption
Affected by Filters: Per the table above, if the graph is affected by the filters, then when the filters are turned on, the graph will revise according to the parameters in the filter

G.2 Analytics Interface

On the Analyze page, users can control and view the following:

Total Calendar Days + Total Cost
Project Cost Distribution: Cost breakdown by labor, equipment, and materials
Average Crew Utilization: Total number of hours all crews worked divided by the total number of hours all crews are available to work
Available Days Worked: Total number of days worked divided by the total number of days some crew is available to work
Total Calendar Days + Total Working Days: working days do not include non-working days
Dropdown menu to select which Analytics Graph is being viewed. The selections are:
- Crew Utilization
- Workforce Utilization
- Material Consumption
- Equipment Utilization
- Crane Utilization
- Cost Over Time
Analytics Graph: controlled by #6 above (dropdown menu)
Cost Breakdown: includes the following:
- Direct Cost (total)
- Idle Cost (total)
- Direct Labor Cost
- Idle Labor Cost
- Direct Equipment Cost
- Idle Equipment Cost
Tasks: includes Total Tasks and Tasks per Day (Tasks / Day)
Export to CSV format: The type of CSV exported depends on the selected dropdown menu
Example: if “Crew Utilization” is selected in the dropdown menu, then the CSV export is for the utilization of the crews

G.3 Crew Utilization

The Crew Utilization Graph provides a daily histogram displaying which crews are performing productive work on site. The graph does not include or show the presence of idle crews on site.

You may use crew filters to switch between the specific graphs for every crew, and if applicable, use the search function to filter by subcontractor.

CSV Export: The CSV export for this graph includes a breakdown of crew utilization by day, by crew, and by subcontractor.

Note: A color scale was added in Excel to the CSV export shown above to make the data more digestible.

G.4 Workforce Utilization

The Workforce Utilization Graph provides a daily histogram displaying the total personpower on site day-by-day grouped by subcontractor. The graph does not include/show the presence of idle crews on site.

CSV Export: The CSV export for this graph includes a breakdown of workforce utilization by day and by subcontractor.

Note: A color scale was added in Excel to the CSV export shown above to make the data more digestible.

G.5 Material Consumption

The Material Consumption graph combines daily histograms of Reusable Materials with cumulative area charts for Consumable Materials in the same graph.

It can be overwhelming to look at all the data at once, and that is why it’s recommended to use material filters to toggle between the visibility of different materials used.

For materials that are consumables, the graph will show the cumulative usage over time.

Example: Consumption of rebar is shown below:

For materials that are reusable, the graph will track the usage over time. Reusable is considered in use for the duration of the activity that uses it only, and then goes back to the pool immediately after. The curve only tracks the usage for activities that “Require” the material and ignores activities that “Supply” it. Consumable is considered taken out of the pool as soon as an activity “Requires” is and is only supplied back to the pool once an activity “Supplies” it.

The curve goes up when activities “require” the material, and back down when activities “supply” the material. If the supply exceeds the demand, the curve does not go below zero.

Example: Reusable slab formwork set is shown below:
CSV Export: The CSV export for the Material Consumption graph includes a day-by-day breakdown for the usage of every material. The breakdown is cumulative for consumable but not for reusable.

G.6 Equipment Utilization

The Equipment Utilization Graph provides a histogram of daily equipment usage. Equipment that is on-site but idle is not shown in the histogram.

Like Crew and Material Consumption, filters can be used to visualize the usage of one or multiple pieces of equipment at a time.

CSV Export: The CSV export will show a day-by-day usage breakdown of every equipment.

G.7 Crane Utilization

The Crane Utilization Graph provides a daily usage of your different cranes on your project.

Current Limitations:

This graph is currently not affected by filters
There is no legend indicating which color refers to which crane. The user can observe the task trays to figure out which crane is represented by which color on the graph.

CSV Export: The CSV export breaks down the day by day usage of each crane.

G.8 Cost Over Time Curve

The Cost Over Time Curve provides a cumulative tally of “as-planned” costs spent over time for any given schedule.

The curve includes multiple lines: Total (black), Labor (red), Idle Labor (purple), Equipment (green), and Material (blue).

By hovering over any of the lines, the tool-tip indicator breaks those down even further to: Labor (Direct + Idle), Equipment (Direct + Idle), and Material (Consumable + Reusable).

CSV Export: While all costs are cumulative in the curve and tooltip, the CSV export provides a day by day utilization that is not cumulative. The columns represent each day, and the rows represent each cost code / category / group. The cost groups are as follows:

For each crew separately:
- Direct Labor Cost
- Idle Labor Cost
- Total Labor Cost
For each Equipment (includes cranes) separately
- Direct Equipment Cost
- Idle Equipment Cost
- Total Equipment Cost
For Materials
- Consumable Cost
- Reusable Cost
Cost Totals Section
- Labor Cost totals by Subcontractor
- Labor Cost totals (all crews from all subs summed up): Total + Direct + Idle
- Equipment Cost totals: Total + Direct + Idle
- Material Cost totals: Consumable + Reusable + Sum of Consumable and Reusable
Project Total

H Schedule Cost Calculations

H.1 Intro to Cost Calculations

One of the most powerful things about ALICE is that we can explore multiple construction strategies and compare their effects on Project Duration and Cost. However, in order to effectively evaluate options, we need to have a solid understanding of how the cost is calculated and the underlying assumptions.

The cost components are broken down into the following:

Total cost
Direct cost
Indirect (Idle) cost

H.2 Total Cost

Total Cost in ALICE is the summation of two main components: Direct Cost & Idle Cost, therefore:

Total Cost = Direct Cost + Idle Cost

Where Direct Cost is the cost spent on value-adding work (more details below) and Idle Cost is the cost spent waiting for work (more details below).

It can be read straight from the explore page (by clicking on a schedule dot), or from the top of the Analyze Page in the Analytics View for each schedule.

In the Analyze Page (Analytics View), Total Cost is also broken down by Labor, Equipment, and Material:

H.3 Direct Cost

Direct Cost for Labor and Equipment

For Labor and Equipment, Direct Cost is calculated as:

Direct Cost = Hourly Cost x Hours Used Productively

Where Hourly Cost is the Cost per hour of the resource and Hours Used Productively are the hours spent doing work rather than waiting (more on waiting below).

A breakdown of Direct Costs by type (Total, Labor, & Equipment) is provided at the bottom of the Analyze page.

You will notice in the example below that:

Direct Labor Cost + Direct Equipment Cost do not add up to Total Direct Cost (add material cost and the total direct cost would add up correctly)
And there is no category for materials

That is because material costs can only be direct and the number can be viewed at the top of the analytics page.

Direct Cost For Material

Consumable Material:

Direct Cost is incurred at the start of every activity that “Requires” this material
No Cost is incurred at the start or end of any activity that supplies this material

Reusable Material:

Direct Cost is incurred equal to the cost of a single resource multiplied by the number actually used by tasks that “require” the resource only

Example:

If on days 1,2,3,4,5,6, the utilization is 0,3,2,0,2,4, then the costs incurred will be 0,3,0,0,0,1 (assuming the unit cost is 1) on the respective days

That is because on day 2 you will buy 3 units that you can reuse on days 3,4,5. But on day 6, you need 4 units, and you had already bought 3, so you need to buy only one more

No Cost is incurred by tasks that supply that resource

Idle Cost

Idle cost is the cost of having a resource (crew or equipment) onsite waiting for work. It’s important to note that the resource is considered onsite the moment it is first needed, and considered off site right after completing the last activity it is needed for.

The easiest way to visualize this is through the graphic below:

So the formula for idle cost becomes:

Idle Cost = (Time on Site - Time Spent Working Productively) x Hourly Cost

Idle costs can be turned off for all or some users from the plan page. See image below. The toggle setting to turn off idle costs is located under Project Resources. If idle costs are toggled off, then only direct costs for that resource type would be taken into account in the project analytics.

9.8.4.1 Idle Cost for Crews vs Equipment

Since Crews only spend their working days onsite, but equipment stays there overnight, we need to make the differentiation when calculating Time onsite.

For Crews, Time onsite only considers the working hours within a Crew’s calendar
For Equipment, Time onsite is 24 hours & 7 days a week cumulative

Therefore, it is very common to have a high idle cost for Equipment even when the schedule is efficient. This is because crews may only be working (and using the equipment) for an approximate standard 8 hours every 24 hours.

The examples below will provide some more clarification:

Example 1: 1 Crew Utilized 100%

Example 2: The Case of Equipment

Example 3: Waiting Time Simplified

Further Resources

On This Page