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Ubiquitous Optimisation. Making Optimisation Easier to Use Prof Peter Cowling http://www.mosaic.brad.ac.uk. Optimisation in Decision Making. Outcomes. Uncontrollable factors. Desirability. Current situation. D4. D3. D2. D1. Controllable factors. Modelling. Conceptual Model.
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Ubiquitous Optimisation Making Optimisation Easier to Use Prof Peter Cowling http://www.mosaic.brad.ac.uk
Optimisation in Decision Making Outcomes Uncontrollable factors Desirability Current situation D4 D3 D2 D1 Controllable factors
Modelling Conceptual Model Reflection Creation Extraction Testing Tangible system Model • Ill-structured • Complex • Abstract • Well-structured • Simple • Concrete
NP-hard Optimisation Operational Research Evolutionary Algorithms Novel Ideas Artificial Intelligence
Does it work? • Oil companies could not survive without optimisation • Manufacturing/transport/logistics/ project management – productivity improvements in the £billions worldwide • Widely and expensively used in finance and management consultancy
Beneficiaries • Any manager or engineer and every decision could benefit from a system which brought useful and usable optimisation. • Consider the proliferation of spreadsheet use among managers/ engineers. • The potential productivity improvements are in the £00,000,000,000s – from improved resource usage, better market targetting, better financial management.
Advances which may bring ubiquitous optimisation closer • Speech/gesture input/output • Intelligent, learning computers • Cognitive science advances • Ambient computing • Control/sensor technologies • Increased IT awareness among managers/engineers
Angles of attack • Hyperheuristics, Software Toolboxes • Reducing the effort and expertise to model and solve problems • Human-computer interaction and cognitive science • Integrating human and artificial intelligence • Dynamic Optimisation – Stability and Utility • Reacting to the dynamic nature of real problems • Gaining real-world problem experience
Hyperheuristics Hyperheuristic Heuristic Choice Low level heuristics L.L. Heuristic performance Solution perturbation Solution quality Problem
Benefits of Hyperheuristics • Low level heuristics easy to implement • Objective measures may be easy to implement – they should be present to raise decision quality • Rapid prototyping – time to first solution low
Concrete example • Organising meetings at a sales summit • Low level heuristics: • Add meeting, delete meeting, swap meeting, add delegate, remove delegate, etc. • Objectives: • Minimise delegates • Maximise supplier meetings
Concrete Example • Hyperheuristic based on the exponential smoothing forecast of performance, compared to simple restarting approaches • Result: 99 delegates reduced to 72 delegates with improved schedule quality for both delegates and suppliers • Compares favourably with bespoke metaheuristic (Simulated Annealing) approach • Fast to implement and easy to modify
Other applications • Timetabling mobile trainers • Nurse rostering • Scheduling project meetings • Examination timetabling
Other Hyperheuristics • Genetic Algorithms • Chromosomes represent sequences of low level heuristics • Evolutionary ability to cope with changing environments useful • Forecasting approaches • Genetic Programming approaches • Artificial Neural Network approaches
Representing constraints Room capacity violation Period limit violation
HuSSH • Allowing users to create their own heuristics “on the fly” • Capturing and reusing successful heuristic approaches allows the decision maker to work at a higher level • User empowerment and satisfaction is raised by these approaches • Users can learn to use sophisticated tools
` user User agent HSM Agent SY Agent coils Hot Strip Mill Slabyard CC-3 Agent CC-1 Agent CC-2 Agent Continuous Casters Slabs Ladle Using Agents
Delete the non-available coils Remaining Scheduled coils Processed coils Reoptimise considering the unscheduled coils Unscheduled coils Schedule Repair
Case studies • SORTED – Nationwide building society • SteelPlanner – A.I. Systems BV • Inventory Management – Meads • Workforce Scheduling - BT • Electronics Assembly - Mion • Nurse rostering – several Belgian Hospitals
Conclusion – Open Problems • Optimisation can improve productivity • Optimisation can be made easier to use and more applicable • Needed: • Robust, widely applicable optimisation algorithms/heuristics • Modelling languages and software toolboxes • Champions and consultants • Better understanding of human problem solving for use in HCI • Higher levels of computer use and literacy