Optimization Constraints and Objects

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

Graphical Scheduling

Constraints

• Resource availability based on whether:
  • Match skill is on (then will pair with skill level required exactly)
  • Keep on interruptible shift name flag is on (then will keep work orders on their required shifts)
  • Match work zone flag is on
  • Model is doing capacity planning or resource leveling (CP will schedule all work orders with additional resources, RL will remove work orders to stay under available resources)
• Dependencies
  • Start to start: predecessor + lag time will start before the successor starts
  • End to end: predecessor + lag time will end before the successor ends
  • End to start: predecessor + lag time will end before the successor starts
  • Start to end: predecessor + lag time will start before the successor ends
• Existing schedule
• Calendar breaks
• Schedule windows
• Location windows
• Work orders interruptible or not
• Asset & location maintenance schedules
• Asset & location operating schedules
• 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 resource leveling, minimize the time between when the last task scheduled is finished and the beginning of the calendar. If the model is doing capacity planning, maximize this time.
2. 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
3. If the flag for priority is on, schedule priority work orders first [flag “Include Priority?”]

Graphical Assignment

Constraints

• Resource availability (i.e. laborers & rotating tools) based on whether:
  • Match skill is on (then will pair with skill level equal to or higher than what is required)
  • Match work zone is on
  • Keep on interruptible shift name is on (then will keep work orders on their required shifts)
• Dependencies
  • Start to start: predecessor + lag time will start before the successor starts
  • End to end: predecessor + lag time will end before the successor ends
  • End to start: predecessor + lag time will end before the successor starts
  • Start to end: predecessor + lag time will start before the successor ends
• Modified availability
• Existing assignments
• Calendar breaks
• Work orders interruptible or not
• Asset & location maintenance schedules
• Asset & location operating schedules
• Schedule windows
• Location windows
• Overall calendar sent (work periods shaped by project start & end dates)
• Travel times (Spatial only)
• Location requirements (Spatial only)

Objectives

1. Minimize time between segments of work orders to keep them together (this keeps them on the same day, or together over multiple days)
2. Maximize the total number of assigned work orders [flag “Maximize the Number of Assigned Work Orders”/ flag “Maximize on Priority Work Orders”]
3. If the flag for priority is on, assign priority work orders first [flag “Maximize on Priority Work Orders”]
4. If the flag for matching on skill is on, try to match work orders to closest skill level possible [flag “Match Skills?”]
5. Minimize the overall time between the start of the first work order and the end of the last work order
6. Minimize the amount of resources used
7. If secondary labor is being used, maximize the number of default laborers used in comparison to the number of non-default laborers [flag “Match on Secondary Labor?”]
8. Minimize the time between the start and end of parent work orders (this keeps child work orders under parent work orders grouped together)