Dynamic Scheduling for Mobile Workforce Management

1. Dynamic Scheduling in Mobile Workforce Management Ralf Keuthen PLANET Information Day, Ulm, 2003

2. Contents • Automated Mobile Workforce Management • The Workforce Scheduling Problem • TASKFORCE System Overview • Issues • Current/Future Work

3. Mobile Workforce Management • a.p.solve -- A Short History • Involved in mobile workforce management since 1987. • Produced two major Work Management Systems which have evolved into the TASKFORCE products we currently market. • a.p.solve (100+ employees) was spun out via the British Telecom’s Brightstar business incubator initiative in April 2003. • a.p.solve’s planning and scheduling products primarily support the management of mobile workers via Personal Digital Assistants and mobile telephony.

4. Scope • Large telecommunication, cable, utility and fix & repair companies typically maintain a fieldforce of 100s - 10,000s of technicians • The fieldforce supplies provision of service, repair and maintenance tasks on a daily basis (between 1000s - 100,000s of tasks/day) • Customers • Residential, Business (provision, repair) • Company itself (maintenance, repair)

5. Example: Mobile Workforce at British Telecom BT Customer Access: • a.p.solve’s TASKFORCE products currently schedule BT’s workforce of Service Technicians. • ~25,000 field technicians • ~150,000 tasks every day across the United Kingdom. • A high quality service at low operational cost needs to be delivered.

6. Work Management Organisation • Domains: Geographical partition of the work area into autonomous domains • Domains controlled by automated work management system • Supervised by a human controller

7. Organisation: How it works Customer Service Work allocation and visualisation Dispatch work to technicians • Handheld terminal • Laptop • Mobile • Call Centre • Network Service TASKFORCE

8. Organisation: How it works • Customer Service: • take customer calls • arrange appointments • TASKFORCE: • provide customer service with a selection of appointment slots • Allocate work to technicians • dispatch work to technicians • Technicians • receive work details • travel to and carry out work • report back when work is finished

9. Workforce Management: From a Scheduling Point of View

10. Scheduling Model • Resources: • Technicians • Vehicles and other equipment • Activities: • provision, repair and maintenance work • Constraints: • time windows, access restrictions • precedence constraints • co-op, assists, etc.

11. Main Objectives Right man - right time - right place - right costs • Maximise productivity • number of tasks scheduled • most efficient resource for each task • Ensure a high quality of service • compliance with agreed appointments & due dates • work importance • - Minimise costs • travel times • waiting/idle times • overtime

12. Other Objectives • Workforce satisfaction • task preferences • preferred working areas • Business rules • every technician gets a job • avoid the splitting of tasks over breaks (if possible) • Avoid disturbances • robust schedules • flexible schedule Some of these contradict one another

13. Issues • Dynamics/Uncertainties/Complexities of problem • Scale • The need for a totally automated, online, system.

14. Dynamics • Tasks The company and its customers can • request • cancel • amend tasks (at all time!!) • Resources Availability subject to last minute changes • personal absence, sick leave, etc • changes to task completion times • vehicle breakdown

15. Uncertainties • Duration of tasks Uncertain due to • exact scale of work often unknown before a technician arrives on site • varying technician skill levels • Travel times Uncertain due to • weather • traffic conditions • Business objectives Resource manager can change business objectives

16. Complexities • Complex mixture of tasks: • different execution target times (appointment/commitments) • different task priorities: low - high priority tasks • Wide range in the duration of tasks: 8 mins - several days • Inter task dependencies can be complex • coops, assists tasks • pre-installation tasks • stock point visits, etc • Site access restrictions • security access • business opening times • road closure, etc

17. Complexities • Geographical complexities • diverse (London vs East Wales, etc) • Preferred working areas • Skills • heterogeneous workforce • diverse skill set • Work type and work skill imbalances • some geographical areas can be under resourced • certain skills can be under resourced • Business Rules

18. Scale Scale of individual problems domain dependent • Technicians: • 10s to 100s of technicians • Tasks: • 100s to 1000s of tasks Scheduler needs to cope efficiently with all domains

19. Issues • No realistic forecasting possible! • Assumed ‘static’ environment? • Optimised schedules quickly become sub optimal or even infeasible • What is optimality in an dynamic environment? • First thing in the morning everything changes !! (sick leave, new tasks, etc) • Building robust/flexible schedules? • Limited applicability • Radical changes to the current schedule may be desired

20. Scheduling Opportunities: Impact of Personal Digital Assistants on Scheduling Practice: • Mobile phones, laptops, handheld terminals, the Internet, etc • allows to dispatch tasks to mobile workers in real time • tasks are (usually) dispatched one by one • Scheduling impact: • allows to adjust the schedule to the changed environment • allows to correct (some) scheduling decisions made earlier However, the time available to react to changes is very limited

21. Available Tools: • Identify processing bottlenecks • Exploit scheduling opportunities • Maintain schedule stability and existing process plans. • Refine solutions. • Repair constraint violations. • Summarise solution states for human controllers and software agents. • Dispatch scheduling tasks to field technicians with respect to current schedule state and customer demand.

22. TASKFORCE System Overview

23. Needed Automation • Automated data flow from order source systems to job dispatch. • Schedule revision must be automatic and robust. • On line Dispatcher must be able to cope with corrupted schedules. • The real-line monitoring of the location of mobile technicians and their expected completion times is important.

24. TASKFORCE Developed by BT and employed since 1997. TASKFORCE supports: • Resource Management • Operations Management • Schedule/Jeopardy Management • Progress Management • Scheduling & Dispatching

25. System Overview

26. Schedule Manager • Planer that transforms customer orders (service requests) into scheduling variables with their associated constraints • Identifies tasks in jeopardy of becoming tardy • Pre-processes tasks & resource information according to business rules • Calls scheduling tools to create/maintain executable schedule

27. Scheduling Needs • Batch Scheduling • Schedule revision • Appointment booking support • Interrupt Scheduling • Route Optimisation • Schedule Dispatcher • What-If Scheduling • Schedule Visualisation & Manual scheduling support

28. Architecture Overview Visualiser Intelligent Appointer DS Optimiser Dispatcher Interrupt Scheduler Pre-scheduler Schedule Manager

29. Batch Scheduler • Runs overnight to construct high quality schedule for the following day • Build provisional start-of-day schedule • Schedule construction & route optimisation • Techniques: • Chronological backtracking based Constructive Algorithm • assign important and hard to schedule tasks • Local Search based optimisation supported by a constraint net to ensure feasibility • Stochastic Local Search: Simulated Annealing

30. Dynamic Scheduler • Run while schedule is being executed to maintain a high quality schedule • Responsibilities: • Absorb schedule changes and most up to date information • Rebuild, repair, update & re-optimise provisional schedule • How it works: • Perform frequent short batch runs to rebuild a feasible schedule • Pass provisional schedule to Schedule Manager

31. Dynamic Scheduler • Pre-scheduling: • Reload and try to rebuild old schedule • Tree Search assigning remaining important and hard to schedule tasks • Optimisation: • Low Temperature Simulated Annealing. Currently looking into more focused techniques such as exploring large neighbourhoods based on an ejection chain model, Guided Local Search, etc

32. Intelligent Appointer • Controller/call centre support tool • Heuristic based • find a set of feasible appointment slots based on the current schedule • suggest feasible appointment slots to human controller • controller books appointment slot and associates time windows with the new task • task is sent to schedule manager

33. Interrupt Scheduler Automatic Schedule Revision: • Reallocation algorithm to support situations where important work would otherwise fail. • The system can’t find an available resource for high priority work at specified times • Interrupt scheduler identifies a sequence of reallocations to free a technician to perform the work

34. Automatic Dispatcher • Online and event triggered System • Responds to requests for work from field force in real-time, making alterations to the planned tour as required. • Supports the management of uncertainties & last second changes to the schedule associated with: • travel time & task duration • arrival of new high priority work and cancellation of already scheduled work

35. Dispatching Algorithms • Rule based system. • If Field Technician request work then the Dispatcher identifies a task for the technician to service. • Rule Examples: • Find work on site for technicians rather than travel to new locations • Give preference to tasks getting close to their deadlines • Keep technicians from travelling outside their preferred working area • etc, etc This may result in the need to repair a damaged schedule

36. What-if and Manual Scheduling • Are off-line schedulers that support work controllers by providing the visual and analysis tools to try out different scheduling parameters and allocations to discover improvement opportunities without risk. • Changes to scheduling parameters can be applied to current or archived data and the resulting schedule can be examined in an off-line environment. • Changes can then be applied to live sites.

37. Schedule Visualisation Tools Compress schedule information and represent it in a way that can easily be captured by the user • Provides the human controller with: • statistics • tour task tables • Gantt chart • map tour representation

38. Schedule Visualisation: Gantt Chart

39. Schedule Visualisation: Map

40. Current/Future Work

41. Dynamic Work Crew Scheduling Field force activities can often not be carried out by a single person but need multi-skilled crews • safety reasons (gas, electric, etc.) • activity reasons (heavy equipment, etc.) • specific equipment (elevator unit, crane, etc) Examples: • Expansion/repair of the telephone network • Electricity/gas/water supply to new build homes • etc.

42. Dynamic Work Crew Scheduling • Workpackages instead of single tasks • Complex workpackages • long tasks (2h to a few weeks) • many inter task dependencies • different configurations possible • Skill matching • is a crew skill the sum of its crew member skills? • Task duration • If 2 people need 1 hour do 4 people need only 1/2 hour? • How and when to build, amend or break crews in a dynamic environment?

43. www.apsolve.com Intelligent End-to-End Fieldforce Automation