dynamic scheduling in mobile workforce management
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Dynamic Scheduling in Mobile Workforce Management. Ralf Keuthen. Contents. Automated Mobile Workforce Management The Workforce Scheduling Problem TASKFORCE System Overview Issues Current/Future Work. Mobile Workforce Management. a.p.solve -- A Short History - PowerPoint PPT PresentationTRANSCRIPT
© British Telecommunications plc 2001
Dynamic Scheduling in Mobile Workforce Management
Ralf Keuthen
© British Telecommunications plc 2001
Contents
Automated Mobile Workforce Management The Workforce Scheduling Problem TASKFORCE System Overview Issues Current/Future Work
© British Telecommunications plc 2001
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.
© British Telecommunications plc 2001
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)
© British Telecommunications plc 2001
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.
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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
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Organisation: How it works
• Call Centre
• Network Service
TASKFORCE
• Handheld terminal
• Laptop
• Mobile
Customer Service
Work allocation and visualisation
Dispatch work to technicians
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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
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Workforce Management: From a Scheduling Point of View
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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.
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Main ObjectivesRight 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
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Other Objectives Workforce satisfaction
task preferences preferred working areas
Business rules every technician gets a job avoid task splitting (when possible)
Avoid disturbances robust schedules flexible schedule
Some of these contradict one another
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Issues
Dynamics/Uncertainties/Complexities of problem
Scale
The need for a totally automated, online, system.
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Dynamics
Tasks
The company and its customers can request cancel amend tasks (at all time!!)
ResourcesAvailability subject to last minute changes personal absence, sick leave, etc changes to task completion times vehicle breakdown
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Uncertainties Duration of tasks
Uncertain due to exact scale of work often unknown before a
technician arrives on site varying technician skill levels
Travel timesUncertain due to weather traffic conditions
Business objectivesResource manager can change business objectives
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Complexities
Complex mixture of tasks: different execution target times (appointment/completeBy) different task priorities: Infill tasks - high priority business 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
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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
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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
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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
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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.
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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
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Reacting to Changes:
Scheduling Opportunities:
Rescheduling
Dynamic scheduling
Real-time scheduling
On-line scheduling
Reactive scheduling
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Reactive Scheduling:
In a stochastic environment, such as human
resource scheduling Reactive scheduling
Monitor changes Analyse impact on current schedule Adjust schedule accordingly
schedule repair focused re-optimisation etc.
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Reactive Scheduling 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.
© British Telecommunications plc 2001
Execution cycle
Monitor
Analysis
Revision
Optimise
Execute
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TASKFORCE System Overview
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TASKFORCE
Developed by BT and employed since 1997.
TASKFORCE supports: Resource Management Operations Management Schedule/Jeopardy Management Progress Management Scheduling & Dispatching
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System Overview
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Scheduling Architecture
Employed scheduling engines:
Intelligent Appointer
Interrupt Scheduler
Dynamic Scheduler
Dispatcher
Visualisation & What-If Scheduling
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Architecture OverviewVisualiser
DS
Pre-scheduler
Optimiser
Interrupt Scheduler
Dispatcher
Intelligent Appointer
Schedule Manager
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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
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Interrupt Scheduler
Automatic Schedule Revision: Reallocation algorithm to support appointment
reservations. A customer requests a technician to attend his
premises between 9am and 12am.
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
Responsibilities: Construct high quality start-of-day schedule Rebuild, repair, update & re-optimise while schedule
is being executed
How it works: Build provisional schedule Perform frequent short batch runs to rebuild a
feasible schedule
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Dynamic Scheduler: Techniques
Pre-scheduling: Reload and try to rebuild old schedule
Tree Search assigning hard to schedule tasks linked tasks, very long tasks, very important tasks
Optimisation: Stochastic Local Search Simulated Annealing.
Currently looking into more focused techniques such as exploring
large neighbourhoods based on an ejection chain model, Guided
Local Search, etc
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Automatic Dispatcher Online and event triggered Rule based system.
If Field Technician request work then the Dispatcher identifies a task for the technician to service.
This invariably results in the need to repair a damaged schedule Schedule analysis will produce state summary reports that
support schedule repair after an unscheduled activity execution.
Focal point Neighbourhood of impact Conflict duration Conflict size
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Schedule Visualisation
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 what-if analysis tools
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Schedule Visualisation: Gantt Chart
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Schedule Visualisation: Map
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Current/Future Work
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Dynamic Work Crew Scheduling
Fieldforce activities can often not be carried out
by a single person but need multi skilled crews security reasons (gas, electric, ladder, etc.) activity reasons (two sides of a cable, heavy
equipment) specific equipment (elevator unit, crane, etc)
Examples: Expansion/repair of the telephone network Electricity/gas/water supply to new build homes etc.
© British Telecommunications plc 2001
Dynamic Work Crew Scheduling
Problems: Complex workpackages (set of linked tasks)
long tasks (2h to a few weeks) many intertask 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, combine or break crews in a changing environment?
© British Telecommunications plc 2001
Incremental Scheduler
Instead of Rescheduling - React to changes immediately Combine scheduling algorithms & dispatcher Basic Idea:
Monitor changes arrival of new tasks resources early or getting delayed tasks moving close to deadlines
React 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)
Intelligent End-to-End Fieldforce Automation
www.apsolve.com