Optimization models description. Constraints, objectives, output.

Note: constraints are equally and definitively enforced while objectives are enforced by the order listed below (1 is highest priority objective)

3 applications/3 optimization models.

• GS-LP to compute work orders start and end time considering finite capacity resources
• GS (extension of GS-LP model) to compute work orders start and end time considering finite capacity resources and some individual resources
• GA (extension of GS model) to compute work orders start and end time and assign tasks to individual resources (labor, crew). Can consider transition time for routing/special problems.

Graphical Scheduling

Constraints

• Resource availability (for craft/crew/tools) based on whether:
• (optional) Match skill (then will pair with skill level required exactly - default)
• (optional) Keep on interruptible shift name (then will keep work orders on their required shifts)
• Match primary labor craft (only)
• Model is doing capacity planning or resource leveling (CP will schedule all work orders with additional resources considering a planning end date, RL will stay under available resources)
• Percent availability time provided as a parameter for RL: removes x% of the end of every work period
• Capacity provided by shift/day. Modified availability at individual level can be considered
• Dependencies
• Start to start: predecessor + lag time will start before the successor starts (or when the successor starts if enforce lead lag)
• End to end: predecessor + lag time will end before the successor ends (or when the successor ends if enforce lead lag)
• End to start: predecessor + lag time will end before the successor starts (or when the successor starts if enforce lead lag)
• Start to end: predecessor + lag time will start before the successor ends (or when the successor ends if enforce lead lag)
• Existing schedule
• Calendar breaks
• Schedule time window (start not earlier, finish not later at work order level)
• Location time window (start not earlier, finish not later at work order level based on the workorder location)
• Work orders interruptible or not
• Requirement duration of work orders can be different from task duration
• (optional) Asset & location maintenance schedules (up time). The location and/or asset of the workorder gives time windows when the work can be performed.
• (optional) Asset & location operating schedules (down time). The location and/or asset of the workorder gives time windows when the work cannot be performed.
• (optional) Force higher priority wo scheduled before lower priority
• Workorders should be performed except if detected infeasible at start
• Overall calendar sent (work periods shaped by project start & end dates; also end date from variables in CP)

Objectives

1. If the model is doing capacity planning, and does not have enough resources to schedule all of the work, then minimize the amount of extra resources used to schedule the rest of the work
2. Minimize the time between when the last task scheduled is finished and the beginning of the calendar.
3. If the flag for priority is on, schedule priority work orders first 

Output

• Work order start/end time
• List of infeasible/unscheduled and filtered out tasks and reason why
• Resource summary report (usage and availability by resource/skill/shift, also extra usage for CP)
• List of conflicts if the model is not feasible (i.e. minimum list of incompatible constraints)
• Alerts (errors, warnings…)

Graphical Assignment

Constraints

• Resource availability (i.e. labor and crew) based on whether:
• (optional) Match skill (then will pair with skill level equal to or higher than what is required)
• (optional) Match work zone. The zone at work order level should be compatible with the zones of the labor/crew (parameter based: all zones, defaults only…)
• (optional) Match labor crafts (primary or secondary)
• (optional) Keep on interruptible shift name (then will keep work orders on their required shifts)
• Modified availability at individual level is considered
• Dependencies
• Start to start: predecessor + lag time will start before the successor starts (or when the successor starts if enforce lead lag)
• End to end: predecessor + lag time will end before the successor ends (or when the successor ends if enforce lead lag)
• End to start: predecessor + lag time will end before the successor starts (or when the successor starts if enforce lead lag)
• Start to end: predecessor + lag time will start before the successor ends (or when the successor ends if enforce lead lag)
• Existing assignments/schedule

• Calendar breaks (For Spatial, breaks are performed at worker home/start location)

• Work orders interruptible or not
• (optional) Asset & location maintenance schedules (up time). The location and/or asset of the workorder gives time windows when the work can be performed.
• (optional) Asset & location operating schedules (down time). The location and/or asset of the workorder gives time windows when the work cannot be performed.
• (optional) Force higher priority wo scheduled before lower priority
• Requirement duration of work orders can be different from task duration

• Schedule time window (start not earlier, finish not later at work order level)
• Location time window (start not earlier, finish not later at work order level based on the workorder location)

• Overall calendar sent (work periods shaped by project start & end dates)
• Travel times (Spatial only)
• Location requirements (Spatial only)

Objectives

1. Maximize the total number of assigned work orders [flag “Maximize the Number of Assigned Work Orders” or flag “Maximize on Priority Work Orders”]
2. Minimize the overall time between the start of the first work order and the end of the last work order
3. Minimize total travel time (Spatial only)
4. If the flag for priority is on, assign priority work orders first [flag “Maximize on Priority Work Orders”]
5. If the flag for matching on skill is on, try to match work orders to closest skill level possible [flag “Match Skills?”]
6. If secondary labor craft is being used, maximize the number of default laborers used in comparison to the number of non-default laborers [flag “Match on Secondary Labor?”]

Output

• Work order start/end time
• Assignments of task to individual resource (labor/crew) by task slices according to shifts and breaks
• Labor summary report (usage and availability by resource/skill/shift/zone)
• List of infeasible/unscheduled and filtered out tasks and reason why
• Alerts (errors, warnings…)

Graphical Scheduling Large Projects

Constraints

• Resource availability (i.e. laborers & crews & rotating tools)
• based on Alternate Availability (capacity by resource/day/(shift)/(skill level))
• Match skill (optional)
• Aircraft zones (Maximo for Aviation only)
• Dependencies
• Start to start: predecessor + lag time will start before the successor starts (or when the successor starts if enforce lead lag)
• End to end: predecessor + lag time will end before the successor ends (or when the successor ends if enforce lead lag)
• End to start: predecessor + lag time will end before the successor starts (or when the successor starts if enforce lead lag)
• Start to end: predecessor + lag time will start before the successor ends (or when the successor ends if enforce lead lag)
• Optimization start date (all workorders scheduled after tis date except if actual dates defined)
• Actuals start and end time (accept capacity overuse at/before optimization start date)
• Calendar breaks

• Work orders time window (start not earlier, finish not later)

• Work orders interruptible or not
• Work orders with preselected shift
• Requirement quantity of work orders can be spread over the task duration if requirement duration is different from task duration
• Workorders have to be performed
• Overall calendar sent (work periods shaped by project start & end dates)

Objectives

(By default, the overall objective is a weighted sum based on weights defined in the optimization panel)

• Minimize turnaround time (full project completion)
• Perform high priority work orders first
• Minimize plan change (based on avoid and limit change time windows parameters)
• Minimize earliness or lateness based on target dates

Output

• Work order start/end time
• KPIs
• List of conflicts if the model is not feasible (i.e. minimum list of incompatible constraints)
• Alerts (errors, warnings…)