MICANTS

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MICANTS

• Gabor Karsai
• Benoit Dawant
• Chris vanBuskirk
• Gabor Szokoli
• Jonathan Sprinkle
• Karlkim Suwanmongkol
• (Vanderbilt/ISIS)

Jon Doyle Robert Laddaga Vera Ketelboeter (MIT)
Russ Currer (Idea Services)
Lt Martin (USMC MAG-13 VMA-513)
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MICANTS Research Goals

• How to use
• Model-Integrated Computing, and
• Agent/Negotiation technology
• to solve complex resource management problems
  in (Autonomic) Logistics
• To demonstrate the feasibility of the technology
  through real-life example(s)

• Roles
• Vanderbilt/ISIS MIC, implementation, and
  demonstration
• MIT Concepts, algorithms
• Boeing Modeling, domain knowledge
• Idea Services Domain expertise and scenarios,
  customer interface
• http//www.isis.vanderbilt.edu/Projects/micants/mi
  cants.htm
• Demo http//www.isis.vanderbilt.edu/Projects/mica
  nts/maplant/index.html

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Application SummaryVision Agent-supported
Maintenance Process
MAPLANT MAintenance PLanning AgeNTs
GoalAssistance through offering negotiated
options
maintains
Commanders Intent
Maintenance Schedule
negotiate
report
W/C OIC
discrepancy
report
Assign mechanic
negotiate
Autonomic response

• Agents
• Helpers for the users
• Implement COs intent, business rules, and user
  guidance
• Negotiate solutions autonomically
• Offer options for approval

negotiate
Flight Schedule
Current focus Negotiation between Flight and
maintenance schedule
Shop Maintenance Schedule
CAUTION Simplified picture
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Resource Allocation ArchitectureScheduling and
negotiation as CSP
Explicit management of constraints during
negotiation/scheduling
Negotiating agent
Other agent
Messaging
Coordination Engine
High-performance encoding techniques
Data structures representing domain constraints
Domain-independent SAT techniques
Schedule
Domain-specific API to the scheduler
Constraint SAT mapper (encoding)
Standard SAT Interface (CNF, etc.)

• Complexity management
• Encoding strategy
• SAT

Standard SAT Problem Solver (Tableau,WSAT,ISAMP)
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ApproachEncoding a scheduling problem as binary
SAT

• Task constraints
• From Maintenance Plan and Manual
• Precedence, Starts after, Ends before, Coherence
• Resource constraints
• Capacity (mechanics and tools)
• Flight requirements
• Guidance
• Preferences for scheduling certain tasks for
  certain times

SCALING Polynomial in Tasks, Resources, Slots
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Resource allocation scheduling problem

• Negotiated, joint scheduling of flight operations
  and maintenance tasks with resource allocation
• Long-term version - IAM-1
• Time span 5 weeks
• A/C allocation w.r.t. usage guidance
• Calendar- and usage-based inspections
• Resource constraints
• Short-term version - IAM-2
• Time span next day
• Based on current status (snapshot) and tomorrows
  flight schedule

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IAM-1 Problem A/C assignment and long-term
scheduling

• Interactive/Automatic A/C assignment
• Flight hour projections
• Usage-based phase calculations
• Risk analysis
• Monthly maintenance planning

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MAPLANT/IAM-1
Data Warehouse
1.Inputs
Guidance
Guidance Knobs
A/C Status
UpcomingInspections
3. Risk analysis
2. Assignments Projections
CFSA
Project Flt Hours
Projected Maint
CFSA View
PFSA
Flt Hours Analysis
Maint Manuals
Overlap Margins
5.Results
4. Maintenance Scheduler
Maintenance Schedule
Resource Margins
Schedule View
Scheduler
Aircraft Availability
MntPlan View
SNAP
Roster
Tools/SE
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MAPLANT/IAM-1Operational scenario

• 1. Maintenance Control Tunes Parameters
• Aircraft Status Tweaks
• Intentionally remove jets from the pool
• Mark downed jets with expected up times
• Partial Flight Schedule Assignment (PFSA)
• Define/Modify Guidance
• 2. Workload Projection
• Complete Flight Schedule Assignment (CFSA)
• Day-By-Day Projection of Accumulated Flight Hours
  per A/C
• Project Scheduled Maintenance Workload (dues
  windows)

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MAPLANT/IAM-1Operational scenario (cont.)

• 3. Risk Analysis Approval of Flight Schedule
• CFSA Analysis (possibly override and re-iterate)
• Resource Margins
• Overlap Margins
• Phase-Phase
• 56-Phase (w/i and across a/c)
• Engine-Phase
• Engine-56
• Aircraft Utilization Rates
• 4. Schedule Computation
• Produces
• Maintenance Schedule
• Aircraft Availability Projection
• Considering
• PFSA Constraints
• Resource Availability
• Resource Margins
• Phase-Phase Overlaps
• Engine-Phase Overlaps

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Aircraft Assignment
1
Each AC has 1. Min, Max, Pref for month 2.
Can/Cannot fly for each day of mo. 3. Optional
deadline with min, max, and pref (takes
precedence over month until it is satisfied)
Assign the ACs to flights, by assigning to the
most desperate ACs first (based up Guidance
info), using the FS for supporting information,
and the Guidance for driving information.
G
AC
Run until all ACs have reached their
minimum, or until no further sorties can be
assigned.
FS
2
Assign the ACs to flights, but this time utilize
the preference of the airplane, instead of a hard
(min) constraint. Similarly, use the Guidance as
driving info, and FS to collaborate.
Run until all ACs have reached their
preference, or until no further Sorties can be
assigned.
FS with detailed sortie info
3
Now, use the FS as the driver, to make sure that
all sorties are assigned, but utilize Guidance to
make sure that max is not exceeded.
Run until all sorties have been assigned, or
until no further Sorties can be assigned.
Flight Schedule
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MAPLANT/IAM-1Screens PRELIMINARY
A/C Status
Flight Schedule/Assignments
Projected Flight Hours
Risks/Overlaps
56 Day
Phase
Engine
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IAM-2 Problem (In the works)Shift change and
short-term scheduling

• Squadron status on demand
• Consider flight schedule mission requirements for
  next shift
• Finalize A/C to mission assignment
• Assign work to Work Centers
• Check impact of decisions

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MAPLANT/IAM-2Operational scenario

• 1. Maintenance Status Check
• A/C status
• Open MAF-s (down and up gripes)
• Upcoming Daily Special and Usage-based
  inspections, phases
• Events
• Start time, duration, A/C requirements
• Operational deviations, pits turns
• 2. Finalize A/C to mission assignment
• Checks legality constraints
• Evaluates assignment with respect to guidance

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MAPLANT/IAM-2Operational scenario (cont.)

• 3. Work assignment to work centers
• View open MAF-s and Other Maintenance Tasks (OMT)
  
• Assign priorities to MAF-s and OMT-s
• Assign MAF-s/OMT-s to Work Centers
• 4. Check impact
• MAPLANT generates maintenance schedule for the
  next shift
• Risk factors calculated from schedule and shown
• MMCO checks and approves schedule
• If needed, MMCO changes priorities, and repeats

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CAMERA / MICANTS Integration Plan
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Demo Scenario (Nov 01)
OPS
Maintenance
Guidance
MAPLANT
SNAP
First Cut Plan
Demo
Demo
Negotiation
Approx. Maintenance Plan (A/C availability)
Refined Ops Plan
Refined Maintenance Plan
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Progress to Date IAM-1

• Flight schedule driven maintenance scheduling
• Manual/automatic A/C to mission assignment under
  guidance goals
• Sophisticated guidance input
• Usage usage projection algorithms
• Scheduling of both calendar- and usage-based
  inspections under resource constraints
• Notify user if constraints fail to request
  guidance
• 5 weeks under 3 minutes
• Generation of A/C availability for second
  iteration with flight scheduler (SNAP)
• Web-based integration framework to support joint
  negotiation between the two system

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MIT MICANTS EFFORTS

• Assisting in coordination with CACE
• Further research on negotiation methods
• Further research on prioritized constraint
  relaxation
• Research on metrics
• Research on models for preferences for
  Commanders Intent

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Commanders Intent

• Commanders generally think in terms of case-based
  reasoning
• Decisions are strongly contextually linked
• Preferences are
• Largely implicit
• Multidimensional
• Interdependent
• More networked than hierarchical

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Approach

• We have investigated detailed scenarios (2)
• The scenarios are sufficiently detailed to state
  clear plans for further action
• The plans are examined to determine questions
  about preferences
• Underlying preferences are exposed and discussed.

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Scenario 1

• Basic elements
• Squadron develops 12 month plan for 1200 flight
  hours
• Plan runs 110 hours/month to achieve goal with 10
  percent leeway
• Squadron achieves 330 hours in first 3 months
• All planes are grounded the whole fourth month
• During the grounding period, the squadron
• Catches up somewhat on maintenance, reducing or
  eliminating backlog of gripes
• Doubles up on maintenance training to permit some
  skipping of Monday half-days when grounding
  period ends
• Gets in all the training lectures for upcoming
  sorties
• Loses some flight qualifications and generally
  gets rusty in skills
• Problem What should be the schedule for the
  remaining 8 months?
• Fly original schedule with no remaining leeway
  for further difficulties?
• Increase rate of flying?
• Ask for more resources?
• Ask for relief from mission?
• Fail to accomplish mission?

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Methods for getting more flight hours into the
schedule

• Lengthen sorties by X
• Changing aircraft configuration (adding tanks,
  etc.)
• Changing sortie profile (high optimal cruise
  burns less fuel)
• Increase flight days
• Fly on Saturdays
• Steal or defer maintenance days
• Move maintenance days to Saturdays
• Increase flight hours per day
• Extend day to more than 10 hours
• Fly more planes (can try flying all available
  planes, including reserves, but risk wasting all
  preparations when one breaks down)

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Commanders Preferences

• General preference order
• Lengthening sorties (from 1.2 to 1.4 hours) is
  best, if this accomplishes core competencies
• Otherwise adding sorties is best
• Among others, avoid increasing op tempo
• Plan A. If we just need hours (e.g., outage
  occurs near end of year when core competencies
  have pretty much been met, but still short on
  hours)
• First, lengthen sorties by profile from 1.2 to
  1.4 hours
• Then, lengthen sorties by configuration
• Then, fly more sorties per day
• Then, defer maintenance training periods
• Plan B. If we need hours plus numbers of specific
  sorties to achieve competencies, then
• First, fly more sorties per day
• Then, fly more days

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Plans

• Timeline
• Early 2002
• Short-term scheduling
• Shift change support
• Later 2002
• Hardening and extensions to support other A/C
  types
• Deployment _at_ Yuma and Iwakuni
• Framework refinements
• New negotiation techniques concurrent constraint
  propagation as negotiation
• Constraints with preferences (MAXSAT or other)
• Sophisticated constraint management in scheduler
• Complexity experiments
• Joint scaling properties (with flight scheduler)

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Screenshots
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A/C Status
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Flight schedule
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Guidance
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Flight hours for missions
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A/C utilization
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Maintenance Plan
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Overlaps
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Maintenance schedule
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Maintenance schedule
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A/C availability