Dynamic Evolution by Constraint Orchestration position...

Problem SituationSolution for Foreseen Coordation

Solution for Unforeseen CoordinationOutlook

Dynamic Evolution by Constraint Orchestrationposition paper

Luuk Groenewegen

Leiden University

Formal Models and Notation for BPEx, SOC and CSCW

Copenhagen, October 20, 2007

joint work with Erik de Vink

Luuk Groenewegen & Erik de Vink Dynamic Evolution by Constraint Orchestration



Outline

Problem situation

Solution for Foreseen Coordination

Solution for Unforeseen Coordination

Outlook




Problem Situation




composite structure diagram

BA

C

pA

pC

pB1

pB2 pA

pC

pB1

pB2

A−B−C

in usual form as collaboration diagram




composite structure diagram

BA

C

A

B

C

pA

pC

pB1

pB2pA

pC

pB1

pB2

A−B−C

pApB1

pB2

pC

A−B−C

in combined form




dynamic consistency in stable situation

T1 T2 T3

dynamic

consistency

type−1

dynamic

consistency

type−2

dynamic

consistency

type−3

hidden

(in component)

role

(at port)2 roles

(at link)

protocol

(collaboration)

A B C DInAStable

Collaboration

DynamicTypes

three types of dynamic consistency problems




dynamic consistency and migration

During

Original

Situation

T2 T3T1

hidden

(in component)

role

(at port)2 roles

(at link)

protocol

(collaboration)

B C DA

? ? ? ?

more types of dynamic consistency problems





During

Original

Situation

During

Migration

T2 T3T1

T2 T3T1

hidden

(in component)

role

(at port)2 roles

(at link)

protocol

(collaboration)

T5 T7T4 T6

A B C D

A B C D

four more dynamic consistency problem types





During

Original

Situation

During

Situation

New

During

Migration

T2 T3T1

T2 T3T1

T2 T3T1

hidden

(in component)

role

(at port)2 roles

(at link)

protocol

(collaboration)

T5 T7T4 T6

T5 T7T4 T6

A B C D

A

A

B C D

DB C

seven dynamic consistency problem types




Solution for Foreseen Coordination




collaboration

Worker1 Worker2 Worker3

CSMcoll

CSM CSM CSM

CSMCoord

Scheduler

architectureand collaboration

critical section management

three workers and one scheduler




local processes

Asg3Chck3

Chck2

Asg1

Chck1continue

continue

continuedisallow

allow

disallow

allow

allowdisallowAsg2

SchedulerWorker1

Worker2

Worker3

PrePost

begin

occupy

finish

pickUplayDown

NCrFree

Crit

worker / scheduler STDsboth of type A dynamics




constraints and constraint composition

Free NCr

Post

Crit

Pre

done

OutCS OutBlck InCS

triv

notYetstarted

done

Free NCr

PrePosttriv

Free NCr

PrePost

notYet

started

OutBlckOutCS InCS

protocol role of worker: type B dynamicssubprocesses checked, enforcing traps




protocol as constraint orchestration

Asg2

Chck2

Worker2(CSM)Worker1(CSM) Worker3(CSM)

triv

started

OutCS

trivdone

Chck1

Chck3disallow

allow

continue

OutCS

OutCSOutCS InCS

OutCSOutCS

OutCS OutCS

?

SchedulerCSMCoord

OutBlck

OutBlcknotYet

OutBlck

traps checked, enforcing subprocessessynchronized roles: type D dynamics




consistency rules

Scheduler : Checkiallow→ Asgi ∗

Workeri(CSM) : OutBlockstarted→ InCS

Scheduler : Asgidisallow→ Checki+1 ∗

Workeri(CSM) : InCSdone→ OutCS,

Workeri+1(CSM) : OutCStriv→OutBlock

Scheduler : Checkicontinue→ Checki+1 ∗

Workeri(CSM) : OutBlocknotYet→ OutCS,

Workeri+1(CSM) : OutCStriv→OutBlock




Solution for Unforeseen Coordination




McPal, stand-by

Content StartMigr

JITting knowChange NewRuleSetObserving wantChange

giveOutphaseAuto

Content StartMigr

JITting knowChange NewRuleSetObserving wantChange

giveOutphaseAuto

during stable collaboration, when no migration occurs




McPal’s evolutionary constraints and protocol rolepartly unknown

Obs

Cntnt

JIT NRS

StMgready

Obs NRS

StMgCntnt

migrDone

ready

migrDone

StatPhase MigrPhase

StatPhase MigrPhase

alternating between foreseen and unforeseen phase




collaboration for evolution

McPal

EvolColl

Worker1

Worker2

Worker3

Scheduler

Evol

Evol

Evol

Evol

Evol

EvolCoord

McPal as manager of all components




consistency rules for McPal

McPal : ObservingwantChange→ JITting

McPal : JITtingknowChange→ NewRuleSet ∗

McPal [Crs : = Crs + Crsmigr + CrstoBe ]

McPal : NewRuleSetgiveOut→ StartMigr ∗

McPal(Evol) : StatPhaseready→ MigrPhase

McPal : ContentphaseOut→ Observing ∗

McPal(Evol) : MigrPhasemigrDone→ StatPhase,

McPal [ Crs : = CrstoBe ]




consistency rules for McPal

McPal : ObservingwantChange→ JITting

McPal : JITtingknowChange→ NewRuleSet ∗

McPal [Crs : = Crs + Crsmigr + CrstoBe ]

McPal : NewRuleSetgiveOut→ StartMigr ∗

McPal(Evol) : StatPhaseready→ MigrPhase

McPal : ContentphaseOut→ Observing ∗

McPal(Evol) : MigrPhasemigrDone→ StatPhase,

McPal [ Crs : = CrstoBe ]




migration coordination as constraint orchestration

Observing

Phase1Phase1Phase1Phase1 JITtingknowChange

NewRuleSetgiveOut

Phase1Phase1Phase1Phase1MigrPhase

StartMigr

?

Observing

W1−Phase2 W2−Phase2 W3−Phase2 Sch−Phase2

W1−Phase2 W2−Phase2 W3−Phase2 Sch−Phase2

wantChange

MigrPhase

McPal

McPal(Evol)Scheduler(Evol)Worker3(Evol)Worker1(Evol) Worker2(Evol)

StatPhase

Content

EvolCoord

ready

migrDone phaseAuto

StatPhase




Outlook




concluding remarks

Paradigm addresses coordination: T1 – T3

McPal addresses migration: T4 – T7

busines and software dynamics treated alike




concluding remarks

process vs service oriented: collaborations forged

migration without quiescence: on-the-fly

migration is consistency-conserving: repeatable

emerging collaboration dynamics: deployable

future workaspect weaving, co-evolution, ArchiMate-UML,reorganization patterns, tool support


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Dynamic Evolution by Constraint Orchestration position...

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