Dynamic Scheduling in Mobile Workforce Management Ralf Keuthen

Dynamic Scheduling in Mobile Workforce Management Ralf Keuthen © British Telecommunications plc 2001

Contents g g g Automated Mobile Workforce Management The Workforce Scheduling Problem TASKFORCE System Overview Issues Current/Future Work © British Telecommunications plc 2001

Mobile Workforce Management g a. p. solve -- A Short History è Involved in mobile workforce management since 1987. è Produced two major Work Management Systems which have evolved into the TASKFORCE products we currently market. è a. p. solve (100+ employees) was spun out via the British Telecom’s Brightstar business incubator initiative in April 2003. è a. p. solve’s planning and scheduling products primarily support the management of mobile workers via Personal Digital Assistants and mobile telephony. © British Telecommunications plc 2001

Scope g g g Large telecommunication, cable, utility and fix & repair companies typically maintain a fieldforce of 100 s - 10, 000 s of technicians The fieldforce supplies provision of service, repair and maintenance tasks on a daily basis (between 1000 s - 100, 000 s of tasks/day) Customers è Residential, Business (provision, repair) è Company itself (maintenance, repair) © British Telecommunications plc 2001

Example: Mobile Workforce at British Telecom BT Customer Access: g a. p. solve’s TASKFORCE products currently schedule BT’s workforce of Service Technicians. g ~25, 000 field technicians g ~150, 000 tasks every day across the United Kingdom. g A high quality service at low operational cost needs to be delivered. © British Telecommunications plc 2001

Work Management Organisation g g g Domains: Geographical partition of the work area into autonomous domains Domains controlled by automated work management system Supervised by a human controller © British Telecommunications plc 2001

Organisation: How it works Customer Service • Call Centre • Network Service Work allocation and visualisation Dispatch work to technicians TASKFORCE • Handheld terminal • Laptop • Mobile © British Telecommunications plc 2001

Organisation: How it works g Customer Service: è take customer calls è arrange appointments g TASKFORCE: è provide customer service with a selection of appointment slots è Allocate work to technicians è dispatch work to technicians g Technicians è receive work details è travel to and carry out work è report back when work is finished © British Telecommunications plc 2001

Workforce Management: From a Scheduling Point of View © British Telecommunications plc 2001

Scheduling Model g Resources: è Technicians è Vehicles g and other equipment Activities: è provision, g repair and maintenance work Constraints: è time windows, access restrictions è precedence constraints è co-op, assists, etc. © British Telecommunications plc 2001

Main Objectives Right man - right time - right place - right costs g Maximise productivity è number of tasks scheduled è most efficient resource for each task g Ensure a high quality of service è compliance with agreed appointments & due dates è work importance g - Minimise costs è travel times è waiting/idle times è overtime © British Telecommunications plc 2001

Other Objectives g Workforce satisfaction è task preferences è preferred working areas g Business rules è every technician gets a job è avoid task splitting (when possible) g Avoid disturbances è robust schedules è flexible schedule Some of these contradict one another © British Telecommunications plc 2001

Issues g g g Dynamics/Uncertainties/Complexities of problem Scale The need for a totally automated, online, system. © British Telecommunications plc 2001

Dynamics g Tasks The company and its customers can è request è cancel è amend tasks (at all time!!) g Resources Availability subject to last minute changes è personal absence, sick leave, etc è changes to task completion times è vehicle breakdown © British Telecommunications plc 2001

Uncertainties g Duration of tasks Uncertain due to è exact scale of work often unknown before a technician arrives on site è varying technician skill levels g Travel times Uncertain due to è weather è traffic conditions g Business objectives Resource manager can change business objectives © British Telecommunications plc 2001

Complexities g Complex mixture of tasks: different execution target times (appointment/complete. By) è different task priorities: Infill tasks - high priority business tasks è Wide range in the duration of tasks: 8 mins - several days è g Inter task dependencies can be complex coops, assists tasks è pre-installation tasks è stock point visits, etc è g Site access restrictions security access è business opening times è road closure, etc è © British Telecommunications plc 2001

Complexities g Geographical complexities diverse (London vs East Wales, etc) è Preferred working areas è g Skills heterogeneous workforce è diverse skill set è g Work type and work skill imbalances some geographical areas can be under resourced è certain skills can be under resourced è g Business Rules © British Telecommunications plc 2001

Scale of individual problems domain dependent g Technicians: è 10 s g to 100 s of technicians Tasks: è 100 s to 1000 s of tasks Scheduler needs to cope efficiently with all domains © British Telecommunications plc 2001

Issues g g No realistic forecasting possible! Assumed ‘static’ environment? è Optimised schedules quickly become sub optimal or even infeasible è What is optimality in an dynamic environment? g g First thing in the morning everything changes !! (sick leave, new tasks, etc) Building robust/flexible schedules? è Limited applicability è Radical changes to the current schedule may be desired © British Telecommunications plc 2001

Needed Automation g g 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. © British Telecommunications plc 2001

Scheduling Opportunities: Impact of Personal Digital Assistants on Scheduling Practice: g Mobile phones, laptops, handheld terminals, the Internet, etc allows to dispatch tasks to mobile workers in real time è tasks are (usually) dispatched one by one è g Scheduling impact: allows to adjust the schedule to the changed environment è allows to correct (some) scheduling decisions made earlier è However, the time available to react to changes is very limited © British Telecommunications plc 2001

Reacting to Changes: Scheduling Opportunities: g Rescheduling g Dynamic scheduling g Real-time scheduling g On-line scheduling g Reactive scheduling © British Telecommunications plc 2001

Reactive Scheduling: In a stochastic environment, such as human resource scheduling g Reactive scheduling è Monitor changes è Analyse impact on current schedule è Adjust schedule accordingly g g g schedule repair focused re-optimisation etc. © British Telecommunications plc 2001

Reactive Scheduling Tools: g g g g 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. © British Telecommunications plc 2001

Execution cycle Monitor Execute Analysis Optimise Revision © British Telecommunications plc 2001

TASKFORCE System Overview © British Telecommunications plc 2001

TASKFORCE Developed by BT and employed since 1997. TASKFORCE supports: g Resource Management g Operations Management g Schedule/Jeopardy Management g Progress Management g Scheduling & Dispatching © British Telecommunications plc 2001

System Overview © British Telecommunications plc 2001

Scheduling Architecture Employed scheduling engines: g Intelligent Appointer g Interrupt Scheduler g Dynamic Scheduler g Dispatcher g Visualisation & What-If Scheduling © British Telecommunications plc 2001

Architecture Overview Visualiser Intelligent Appointer DS Optimiser Dispatcher Pre-scheduler © British Telecommunications plc 2001 Schedule Manager Interrupt Scheduler

Intelligent Appointer g g Controller/call centre support tool Heuristic based è find a set of feasible appointment slots based on the current schedule è suggest feasible appointment slots to human controller è controller books appointment slot and associates time windows with the new task è task is sent to schedule manager © British Telecommunications plc 2001

Interrupt Scheduler Automatic Schedule Revision: g Reallocation algorithm to support appointment reservations. èA customer requests a technician to attend his premises between 9 am and 12 am. è The system can’t find an available resource between these hours but can identify a sequence of reallocations to free a technician to attend the customer. © British Telecommunications plc 2001

Dynamic Scheduler: Repair/Optimisation g Responsibilities: è Construct high quality start-of-day schedule è Rebuild, repair, update & re-optimise while schedule is being executed g How it works: è Build provisional schedule è Perform frequent short batch runs to rebuild a feasible schedule © British Telecommunications plc 2001

Dynamic Scheduler: Techniques g Pre-scheduling: è Reload g Tree Search assigning hard to schedule tasks è linked g and try to rebuild old schedule tasks, very long tasks, very important tasks Optimisation: è Stochastic Local Search è Simulated Annealing. Currently looking into more focused techniques such as exploring large neighbourhoods based on an ejection chain model, Guided Local Search, etc © British Telecommunications plc 2001

Automatic Dispatcher g g Online and event triggered Rule based system. è If Field Technician request work then the Dispatcher identifies a task for the technician to service. g This invariably results in the need to repair a damaged schedule è Schedule analysis will produce state summary reports that support schedule repair after an unscheduled activity execution. è Focal point è Neighbourhood of impact è Conflict duration è Conflict size © British Telecommunications plc 2001

Schedule Visualisation Compress schedule information and represent it in a way that can easily be captured by the user g Provides the human controller with: è statistics è tour task tables è Gantt chart è map tour representation è what-if analysis tools © British Telecommunications plc 2001

Schedule Visualisation: Gantt Chart © British Telecommunications plc 2001

Schedule Visualisation: Map © British Telecommunications plc 2001

Current/Future Work © British Telecommunications plc 2001

Dynamic Work Crew Scheduling Fieldforce activities can often not be carried out by a single person but need multi skilled crews è security reasons (gas, electric, ladder, etc. ) è activity reasons (two sides of a cable, heavy equipment) è specific equipment (elevator unit, crane, etc) Examples: g Expansion/repair of the telephone network g Electricity/gas/water supply to new build homes g etc. © British Telecommunications plc 2001

Dynamic Work Crew Scheduling Problems: g Complex workpackages (set of linked tasks) è long tasks (2 h to a few weeks) è many intertask dependencies è different configurations possible g Skill matching è is g Task duration è If g a crew skill the sum of its crew member skills? 2 people need 1 hour do 4 people need only 1/2 hour? How and when to build, combine or break crews in a changing environment? © British Telecommunications plc 2001

Incremental Scheduler Instead of Rescheduling - React to changes immediately g g Combine scheduling algorithms & dispatcher Basic Idea: è Monitor g g g arrival of new tasks resources early or getting delayed tasks moving close to deadlines è React g g g changes to changes in real time insert new tasks once they arrive move tasks that are getting likely to failure re-optimise parts of the schedule (focused local search) © British Telecommunications plc 2001

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