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Production Scheduling: location of the user in the decision-making architecture. Peter G. Higgins. Outline. Standard scheduling software features design criteria Real scheduling environment Decision Architecture Cognitive Work Analysis. Heuristic produces sequence. Scheduling Rules. - PowerPoint PPT Presentation
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Production Scheduling: location of the user in the decision-making architecture
Peter G. Higgins
Outline
• Standard scheduling software– features– design criteria
• Real scheduling environment• Decision Architecture• Cognitive Work Analysis
Heuristicproducessequence
Standard Decision Architecture
Scheduling Rules
GANTTCHARTTiming at
resourcesPerformance
prediction
Normative Design Criteria
• Operations Research Model– few attributes
• due date• processing time
• Goals– maximise resource utilisation– minimise tardiness
• Heuristics – tendency to meet goals for simple problems
• all jobs available• single resource
Real Scheduling
• Complex– especially job shops
• Uncertainties– job arrivals, material availability, processing & set-up times
• Perplexity– multiple goals
• conflict• importance varies
Standard Solution for Mismatch between Design Model and Reality
• Human moves jobs using mouse
• Locate human activity centrallyhuman activity centrally in the decision-making process– computer: data representation, heuristics, rules
• Use Cognitive Work AnalysisCognitive Work Analysis to analyse the work domain and decision-making activities in complex systems in which there are many competing and conflicting goals.
• Use theories of significationsignification to inform interface design.
Decision Architecture for Real Environments
GANTTCHARTTiming at
resourcesPerformance
prediction
JOBSWINDOWS
Machine nSequenceJob attributes
Machine 1SequenceJob attributes
UnassignedSequenceJob attributes
Scheduling Rules Knowledge-Based Adviser
HUMAN DECISION MAKING Context Setting
Pattern Recognition
Decision Architecture
Tardiness
WeightedTardiness
NetWeightedTardiness
Resource’sWeightedTardiness
Timeconstraint
onDue date
Earliest Due Date
Due Date
Detailed data in
pop-up
Visible ondouble clicking
Visible ondouble clicking
Complexity and Perplexity of the Real Domain
• Apply Cognitive Work Analysis
P e r f o r a t e
O u t p u tF a n - f o l df o r m s
O u t p u tS h e e t e df o r m s
C o n t i n u o u sp r i n t i n g
S h e e tp r i n t i n g
P r o c u r eS h e e t P a p e r
P r o c u r eC o n t i n u o u sP a p e r C o l l a t e
& f i n i s hC u t i n t os h e e t
S p e c i a lF i n i s h
F o l d
C u t
B o x e dF a n - f o l df o r m s
B o x e dS h e e t e df o r m s
T r i d e n t
M i n a m i
H u n k e l e r
B o w e
A K I R AR e e l o fp a p e r
S t o r e
S t a c ko fp a p e r
S t o r e
S a n d e n
EndsEnds
MeansMeans
PhysicalPhysicalDeviceDevice
PhysicalPhysicalFunctionFunction
Functional purpose
Priority/
Values
Purpose related function
Maximise short-term financial viability
Maximise repeat custom
Maximise long-term financial return
Physical function
Physical device
Fold
Perforate
Cut
Plates
Folder
Cross Perforator
Cutter
Ink
Cyl.
paper
speed
Cross Perforator
Fold
Perforate
Cut
Plates
Folder
Cross Perforator
Cutter
Ink
Cyl.
paper
speed
Cross Perforator
Fold
Perforate
Cut
Plates
Folder
Cross Perforator
Cutter
Ink
Cyl.
paper
speed
Cross Perforator
Fix
UV
Fold
Perforate
Cut
Plates
Folder
Cross Perforator
Cutter
Ink
Cyl.
paper
speed
Cross Perforator
Process paper to specified attributes
Job n
dd
D
W
Q
FOB1
FOB4
BOB1
BOB4
···
Cust
jobno
Parts
SbS
To Plates
Plates available
Paper
···
AKIRA1 AKIRA2 AKIRA3 AKIRA4
OPTIONS
EFFECTS
Evaluate options
Predict
consequences
Identify state
Choose task
TASK
PROCEDURE
Plan
Execute
INFORMATION
Observe
data/evidence
Activation
Desired State
Goals
Alert:
Actual State
Goal:Goal:Low press set-up timeLow press set-up time
Scan available jobsScan available jobs
Identify set of jobsIdentify set of jobs requiring currentrequiring current
major set-upmajor set-up
Activity Analysis #1Activity Analysis #1
Many feasible goalsMany feasible goals
Low press set-up timeLow press set-up time Particular jobs meetParticular jobs meet their due datetheir due date
OPTIONS
EFFECTS
Evaluate options
Predict
consequences
Identify state
Choose task
TASK
PROCEDURE
Plan
Execute
INFORMATION
Observe
data/evidence
Activation
Desired State
Goals
Alert:
Actual State
Activity AnalysisActivity Analysis
1A
2D
1D
Maximise long-term financial return
2A
3A
4A
5A
8A
7A
6A
10A
9A
12A
11A
13A
14A
15A
8B
9B
1B
7B
6B
2B
4B
5B
3B
1C
3C
2C
Low press idle timeLow press idle time
Low press set-up timeLow press set-up time
Fully utilise all machinesFully utilise all machines
Maximise productivityMaximise productivity
Maximise short-term Maximise short-term financial viabilityfinancial viability
Goal StructureGoal Structure
Functional purpose
Priority/
Values
Purpose related function
Maximise short-term financial viability
Maximise repeat custom
Maximise long-term financial return
Physical function
Physical device
Fold
Perforate
Cut
Plates
Folder
Cross Perforator
Cutter
Ink
Cyl.
paper
speed
Cross Perforator
Fold
Perforate
Cut
Plates
Folder
Cross Perforator
Cutter
Ink
Cyl.
paper
speed
Cross Perforator
Fold
Perforate
Cut
Plates
Folder
Cross Perforator
Cutter
Ink
Cyl.
paper
speed
Cross Perforator
Fix
UV
Fold
Perforate
Cut
Plates
Folder
Cross Perforator
Cutter
Ink
Cyl.
paper
speed
Cross Perforator
Process paper to specified attributes
Job n
dd
D
W
Q
FOB1
FOB4
BOB1
BOB4
···
Cust
jobno
Parts
SbS
To Plates
Plates available
Paper
···
AKIRA1 AKIRA2 AKIRA3 AKIRA4
OPTIONS
EFFECTS
Evaluate options
Predict
consequences
Identify state
Choose task
TASK
PROCEDURE
Plan
Execute
INFORMATION
Observe
data/evidence
Activation
Desired State
Goals
Alert:
Actual State
Goal StructureGoal Structure
Human Human normally normally operates with operates with these goalsthese goals Visualisation of measuresVisualisation of measures
of performanceof performance
Goal structure used to design DSSGoal structure used to design DSS
Visualisation:Visualisation:performance ofperformance of
higher level goalshigher level goals
Functional purpose
Priority/
Values
Purpose related function
Maximise short-term financial viability
Maximise repeat custom
Maximise long-term financial return
Physical function
Physical device
Print Fold
Perforate
Cut
Plates
Folder
Cross Perforator
Cutter
Ink
Cyl. paper speed
Cross Perforator
Print Fold
Perforate
Cut
Plates
Folder
Cross Perforator
Cutter
Ink
Cyl. paper speed
Cross Perforator
Print Fold
Perforate
Cut
Plates
Folder
Cross Perforator
Cutter
Ink
Cyl. paper speed
Cross Perforator
Fix
UV
Print Fold
Perforate
Cut
Plates
Folder
Cross Perforator
Cutter
Ink
Cyl. paper speed
Cross Perforator
Process paper to specified attributes
Job n dd
D
W
Q
FOB1
FOB4
BOB1
BOB4
···
Cust
jobno
Parts
SbS
To Plates
Plates available
Paper
···
AKIRA1
AKIRA2
AKIRA3
AKIRA4
Printing example shows the complexity
Benefits of this approach
• The pursuit of goals and enforcement of constraints that are difficult to represent computationally
• The following of methods that schedulers find natural • The freedom for schedulers to use their intuition
earliness
tardinessweight
weight tardiness
structural sequence
cylinder set-up time
perforator set-up time
1
2 3
4
Constraints differ between abstraction hierarchies
AI model
• Constraint satisfaction• simulation• problem of rule management
– made-to-order or customised– expensive– difficult to maintain
