Advanced Scheduling Technology for Shorter Resource Constrained Project

Advanced Scheduling Technology for Shorter Resource Constrained Project Durations Presented by: Robert Richards, Ph. D. Richards@Stottler. Henke. com www. Stottler. Henke. com AACE International’s 52 nd Annual Meeting and ICEC’s 6 th World Congress on Cost Engineering, Project Management, and Quantity Surveying

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Stottler Henke: Background & Perspective • • Software company Not Project Management Professionals Artificial Intelligence Research & Development Video 2

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Resources & CPPM/CCPM • • Large organizations developing and building complex systems rely on schedules and project management. Many CPPM projects are resource constrained (in reality, even if not modeled that way) Critical Chain Project Management always considers resources Resource constraints (e. g. , labor, space, equipment) greatly complicates the scheduling problem. – Hence a ‘reason’ to ignore 3

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Where in the PM Space? • Project Management – … – Critical Path (Resource Constrained) or Critical Chain • … • Scheduling / Level Resources • … – … 4

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Scheduling Background / Comparisons • Resource-Constrained Scheduling is NP-Complete, takes exponential time for optimal solution – I. e. , it is a hard problem – Approximate methods are needed • Most automatic scheduling systems use simple one-pass algorithms • Standard constraint-based approaches are far less computationally efficient (Aurora takes advantage of structure of scheduling problems and heuristics) 5

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Why Important? • So much work is put into developing project plan before hitting the schedule / Level Resources … button Days, Weeks, Months • What if your resulting schedule is 10% longer than it needs to be because of the scheduling engine? • Would you care? 6

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress How about 25% longer? 7

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress How about 50% longer? 8

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress How about 100% longer? 9

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Real World Example • Following figure shows. – Critical Path – Resource Constrained Critical Path / Critical Chain (both theoretically correct) • The goal is the shortest correct schedule 10

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Scheduling Engine Comparison 11

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Benefits of Sophisticated Underlying Scheduler • • Results in a better initial schedule Execution: Schedule is more flexible and better able to accommodate change. – Schedule is “self-aware” of what tasks can most easily be moved. I. e. , tasks store information about what placed it where it is placed. – Quickly reschedule as if resources on late task are not available until after its estimated end time. – Example: • Long task requiring resource X is delayed, later task(s) that needs X was only placed there due to resource limitation NOT logical link, so now later tasks can be performed if scheduler is smart enough. 12

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Example from Literature Critical Path = 1 + 5 =7 1 resource 5 total units Resource leveling – Task 4 needs 2 Task 3 needs 2, now only 1 resource left, luckily Task 1 only needs 1 13

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Example from Literature • • Critical Path = 1 + 5 =7 1 resource 5 total units MS Project 2003 & 2007 result = 9 units of time Aurora result = 8 units of time 14

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Results: Example from Literature • • Critical Path 7 units of time MS Project 2003 9 units of time MS Project 2007 9 units of time Primavera P 6 8 units of time – Performed by 3 rd party • • Aurora Optimal 8 units of time 7 units of time 15

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Aurora – NASA Heritage • • Many capabilities developed for NASA Used by NASA – – • Space Shuttle refurbishment Used in launch scheduling Used in International Space Station Part of Mars mission with United Space Alliance Used by Boeing & others – B 787 Dreamliner final assembly 16

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Example Constraint Types • • • Temporal constraints Resource constraints Labor constraints Usage constraints – e. g. , tool can only be used for so many hours continuously and/or during a day. Spatial constraints – e. g. , – job requires a certain location or type of space; – two elements should (or should not) be next to each other • Ergonomic constraints – individual limitations on work conditions 17

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Lessons Learned: Aurora Scheduling Heuristics • • • Heuristics – Suite of heuristics developed over years found to be critical to finding a high-quality schedule quickly. Most heuristics are generally applicable – domain tailored heuristics can further improve quality/speed. Heuristics used in each stage of the scheduling process. 18

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Aurora Scheduling Engine Architecture 19

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Aurora: Screenshot 20

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Example: Critical Chain and Advanced Planning & Scheduling • • • Resource-Constrained Critical Path / Critical Chain and project duration determination by 4 different tools. Every program correctly built a Resource-Constrained Critical Path schedule. In the following figure, – Shortest Resource-Constrained Critical Path = 100 units of time – Longest Resource-Constrained Critical Path = 110 units of time 21

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress 22

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Example: Professor Lu’s Case Study • Real construction project in Hong Kong – – Box culvert construction Total 33 activities 8 types of resources (i. e. laborers, crane, backhoe, roller, etc. ) Multiple resource calendars • Laborers & carpenters (6 d/w) • Concreting laborers (4 d/w) 23

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Professor Lu’s Optimization Results Summary i) Objective: minimizing total project duration Base case: Activity priority suggested by P 3 Exp. 1: Adjust activity priority 4 4 3 2 5 1 8 4 Total project duration (d) 283 275 Total project cost (Hong Kong dollars) [direct cost & indirect cost] 13, 992, 750 [9. 45 M & 4. 55 M] 13, 508, 600 [9. 01 M & 4. 43 M] Computing time (sec) / 15 Scenario Resource Bar benders Backhoes Cranes Carpenters Concreting laborers Drainlayer Skilled laborers Rollers ~ 3% difference 24

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Professor Lu’s Results • Real world example with 33 tasks his scheduling engine shows > 3% improvement. 25

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Example: Commercial Construction Project Plan • • 145 activities Available from – http: //office. microsoft. com/en-us/templates/TC 010184451033. aspx 26

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Commercial Construction Project Plan: Network in Aurora 27

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Results: Commercial Construction Project Plan • • MS Project 2007 358 days Aurora 355 days 28

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Example: 300 Tasks Aerospace Application • Multiple resource types needed for most tasks 29

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress 300 Task Example: Network in Aurora 30

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Results: 300 Task Example • • • MS Project 2003 145. 6 days MS Project 2007 145. 6 days Aurora 102. 5 days 31

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Results • • Multiple sources reveal the effect of the Scheduling Engine For larger projects (>1, 000): Aurora has been able to find project durations 50% shorter than other software for the same data set. Much of the potential improvement offered by modeling resources is being squandered. Resource leveled schedules are sub-optimal 32

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Planning & Execution • • Initial Schedule benefits Execution benefits even MORE – If scheduler is inefficient, every delay will be magnified because re-allocation of resources will be deficient 33

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress Take Aways • Scheduling engine is critical. • Paying up to 100% penalty due to the scheduling engine. • Changing to an improved scheduling engine is probably the greatest potential improvement available to your project. • Use more than 1 scheduling engine. 34

AACE International’s 52 nd Annual Meeting & ICEC’s 6 th World Congress The Authors • Annaka Kalton Stottler Henke • Robert Richards, Ph. D. Stottler Henke Richards@Stottler. Henke. com 35