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

ns

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)

Screenshots

A/C Status

Flight schedule

Guidance

Flight hours for missions

A/C utilization

Maintenance Plan

Overlaps

Maintenance schedule

Maintenance schedule

A/C availability