MICANTSGabor KarsaiBenoit DawantChris vanBuskirkGabor SzokoliJonathan SprinkleKarlkim Suwanmongkol(Vanderbilt/ISIS)
Jon DoyleRobert Laddaga Vera Ketelboeter(MIT)Russ Currer (Idea Services)
Lt Martin (USMC MAG-13 VMA-513)
MICANTS Research Goals• How to useHow to use
1.1. Model-Integrated Computing,Model-Integrated Computing, and and 2.2. Agent/Negotiation technologyAgent/Negotiation technology
to solve complex resource management problems in to solve complex resource management problems in (Autonomic) Logistics(Autonomic) Logistics
• To demonstrate the feasibility of the technology To demonstrate the feasibility of the technology through through real-lifereal-life example(s) example(s)
Roles Vanderbilt/ISIS: MIC, implementation, and demonstration MIT: Concepts, algorithms Boeing: Modeling, domain knowledge Idea Services: Domain expertise and scenarios, customer interfacehttp://www.isis.vanderbilt.edu/Projects/micants/micants.htmDemo: http://www.isis.vanderbilt.edu/Projects/micants/maplant/index.html
Application SummaryApplication SummaryVision: Vision: Agent-supported Maintenance ProcessAgent-supported Maintenance Process
discrepancy report
MMCO
Flight Schedule
Shop Maintenance
Schedule
Assign mechanic
negotiate
negotiate
W/C OIC
Goal:Assistance through offering negotiated options
optio
ns
appro
ve
repo
rt
optio
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appro
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negotiate
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Autonomic response
MMCO(sister
squadron)
Agents:•“Helpers” for the users•Implement CO’s intent, business rules, and user guidance•Negotiate solutions autonomically•Offer options for approval
Commander’s
Commander’sIntentIntent
CAUTION: Simplified CAUTION: Simplified picturepicture
CAUTION: Simplified CAUTION: Simplified picturepicture
MAPLANTMAintenancePLanningAgeNTs
Maintenance Schedule
maintains
Current focus:Negotiation between Flight and maintenance schedule
Resource Allocation ArchitectureScheduling and negotiation as CSP
Negotiating agent
Messa
gin
g
CoordinationEngine
Data structures representing
domain constraints
ConstraintSAT
mapper (encoding)
Standard SATProblem Solver
(Tableau,WSAT,ISAMP)
Standard SATProblem Solver
(Tableau,WSAT,ISAMP)
Explicit management of
constraints during negotiation/scheduli
ng
“High-performance”encoding techniques
Domain-independent
SAT techniques
Standard SAT Interface (CNF, etc.)
Schedule
Domain-specific API to the scheduler
Complexity management:Encoding strategySAT
Otheragent
MMCO
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
SCALINGSCALING: Polynomial in #Tasks, #Resources, #Slots
Resource allocation & scheduling problem
Negotiated, joint scheduling of flight operations and maintenance tasks with resource allocation
1. Long-term version: - IAM-1 Time span: 5 weeks A/C allocation w.r.t. usage guidance Calendar- and usage-based inspections Resource constraints
2. Short-term version: - IAM-2 Time span: next day Based on current status (snapshot) and
tomorrow’s flight schedule
IAM-1 Problem: A/C assignment and long-term scheduling
1. Interactive/Automatic A/C assignment
2. Flight hour projections3. Usage-based & phase
calculations4. Risk analysis5. Monthly maintenance planning
3. Risk analysis
5.Results
MAPLANT/IAM-1
1.Inputs2. Assignments & Projections
4. Maintenance Scheduler
DataWarehouse
GuidanceKnobs
A/C Status
CFSAProject
Flt HoursPFSA
UpcomingInspections
ProjectedMaint
CFSAView
OverlapMargins
ResourceMarginsScheduler
SNAP
Flt HoursAnalysis
MntPlanView
MaintManuals
RosterTools/SE
Guidance
ScheduleView Aircraft Availability
Maintenance Schedule
MAPLANT/IAM-1Operational scenario1. 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 ProjectionComplete Flight Schedule Assignment (CFSA)
Day-By-Day Projection of Accumulated Flight Hours per A/C
Project Scheduled Maintenance Workload (dues windows)
MAPLANT/IAM-1Operational scenario (cont.)3. Risk Analysis & Approval of Flight Schedule
CFSA Analysis (possibly override and re-iterate)
Resource Margins
Overlap MarginsPhase-Phase56-Phase (w/i and across a/c)Engine-PhaseEngine-56
Aircraft Utilization Rates
4. Schedule ComputationProduces
a.Maintenance Schedule
b.Aircraft Availability Projection
Consideringa.PFSA Constraints
b.Resource Availability
c.Resource Margins
d.Phase-Phase Overlaps
e.Engine-Phase Overlaps
Guidance
Each AC has:1. Min, Max, Pref for month2. Can/Cannot fly for each day of mo.3. Optional deadline with min, max,
and pref (takes precedence over month until it is satisfied)
Fleet Info
Gives AC types (day, night, radar)
FlightSchedule
FS with detailed sortie info
G AC
FS
Run until all AC’s have reached their minimum,or until no further sorties can be assigned.
Assign the AC’s to flights, by assigning to the most desperate AC’s first (based up Guidance info), using the FS for supporting information, and the Guidance for driving information.
1
Assign the AC’s 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.
2
Run until all sorties have beenassigned, or until no further Sorties can be assigned.
Run until all AC’s have reached their preference, or until no further Sorties can be assigned.
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.
3
Aircraft Assignment
MAPLANT/IAM-1Screens – PRELIMINARYA/C Status Flight Schedule/Assignments
Projected Flight Hours
56 DayPhaseEngine
Risks/Overlaps
IAM-2 Problem: (In the works)Shift change and short-term scheduling
1. Squadron status on demand2. Consider flight schedule mission
requirements for next shift3. Finalize A/C to mission assignment4. Assign work to Work Centers5. Check impact of decisions
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
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
CAMERA / MICANTS Integration Plan
The two systems interact using a well-defined messaging protocol to facilitate negotiation between the flight schedule and maintenance schedule. The objective is to explore trade-offs between the two aspects to achieve global optimization w.r.t. some metric (e.g., generation rate, CRP, etc.)
Negotiation between MAPLANT and SNAP
5.
MAPLANT provides a "best effort“ estimates for the number aircrafts, their capabilities, other attributes, and negotiable and non-negotiable constraints associated with them. SNAP creates a schedule based on this.
Scheduling flight operations based on plane availability and capabilities
4.
MAPLANT provides a "best effort" estimates for the number of available aircrafts over time. SNAP creates a schedule based on these estimated generation rates.
Scheduling flight operations based on plane availability
3.
SNAP supplies n-week flight schedule to MAPLANT which uses that to generate a long term maintenance plan
Scheduling/planning of long-term, strategic, scheduled maintenance actions w.r.t. long-term flight schedule
2.
SNAP supplies daily flight schedule to MAPLANT which in turn generates a daily maintenance plan
Scheduling/planning of short-term, tactical, corrective maintenance actions in light of the flight schedule
1.
Demo Scenario (Nov ’01)
OPSMaintenance
Guidance
MAPLANT SNAP
First Cut Plan
Refined Ops Plan
Approx. Maintenance Plan (A/C availability)
Refined Maintenance Plan
DemoDemoN
eg
oti
ati
on DemoDemo
Progress to Date: IAM-1Flight schedule driven maintenance schedulingManual/automatic A/C to mission assignment under guidance goalsSophisticated guidance inputUsage usage projection algorithmsScheduling of both calendar- and usage-based inspections under resource constraintsNotify user if constraints fail – to request guidance5 weeks under 3 minutesGeneration of A/C availability for second iteration with flight scheduler (SNAP)Web-based integration framework to support joint negotiation between the two system
MIT MICANTS EFFORTS
Assisting in coordination with CACEFurther research on negotiation methodsFurther research on prioritized constraint relaxationResearch on metricsResearch on models for preferences for Commander’s Intent
Commander’s Intent
Commanders generally think in terms of case-based reasoningDecisions are strongly contextually linkedPreferences are: Largely implicit Multidimensional Interdependent More networked than hierarchical
Approach
We have investigated detailed scenarios (2) The scenarios are sufficiently detailed to state clear plans for further actionThe plans are examined to determine questions about preferencesUnderlying preferences are exposed and discussed.
Scenario 1Basic 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?
Methods for getting more flight hours into the schedule
Lengthen sorties by XChanging 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)
Commander’s 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
PlansTimeline
Early 2002: Short-term scheduling Shift change support
Later 2002: Hardening and extensions to support other A/C types Deployment @ 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)