Development of Rigorous Adaptive Information Systems

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Development of Rigorous Adaptive Information Systems. Dr. Nasreddine Aoumeur FIN, ITI, DB group aoumeur@iti.cs.uni-magdeburg.de Course Site: wwwiti.cs.uni-magdeburg.de/~aoumeur wwwiti.cs.uni-magdeburg.de/iti_db/lehre/oois/inde. Information Systems: Working definition.
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Development of Rigorous Adaptive Information SystemsDr. Nasreddine AoumeurFIN, ITI, DB groupaoumeur@iti.cs.uni-magdeburg.deCourse Site: wwwiti.cs.uni-magdeburg.de/~aoumeur wwwiti.cs.uni-magdeburg.de/iti_db/lehre/oois/inde... Information SystemsInformation Systems: Working definition
  • reactive systems (i.e. in continuous interaction with their environment), with
  • large amount of immutable and non-immutabledata(i.e. fixed and changing) and, with
  • processes and activities for exhibiting behaviors on these (state-less and –full) data.
  • ... Information SystemsDifferent generations of CMs : “Entity first”Entity-Relationship[1973..] - Intuitive / Simple - Revolutionary for IS - UoD : Entities+Relations - Mathematically sound - Rich abstraction mechnanisms - Different variants (NIAM / SADT / MERISE / ..)IS Conceptual ModelState-less and -ful DATAProcess-centric Formalisms - CCS, CSP, DFD, Petri Nets, .. - Synchronous / asynchronous - Mathematically sound - Executable / operationalProcesses and Rules... Information SystemsDifferent generations of CMs : “Object first”Object Paradigm[1980..] - Really Intuitive / highly accepted - Object (Id, structure / dynamic) - UoD : Interacting objects community - Rich abstraction mechnanisms (e.g. Class, inheritance, role, aggregation, ..) - Different formal interpretations IS Conceptual ModelState-less and -ful DATABehavior-centric OO Formalisms - OO Petri Nets, Mondel, JSD.. - Mathematically sound - Executable / operational / concurrent - Cope with data and process around objectsProcesses and Rules... Information SystemsCurrent generation of CMs : “Interaction first”Aspect/archietctural Paradigm - Explicit separation betweenCoordination and computation - Separation between what is evolving from what is stable - Dynamic shifting-down / up of changing behavior - Suitable for services and mobilityIS Conceptual ModelAspect-/connector-/meta-levelAll What is :- Evolving (business rules, market laws, cross-organizational policies, …) - Cross-Cutting (security, management,..) - Non-functional (availability, performance,..)Stable and invariantentitiesDynamically weavingEntity Interfaces... Information SystemsFirst generation of CMs : “Entity first”E/R Conceptual ModelEntity NameAttribute1 : Type1Attribute2 : Type2....Attributei : Typein-mPARTi-jAssocm Entit(ies)Property1.....IS-An Entit(ies)Processes and Rules... Information SystemsFirst generation of CMs : “Entity first”E/R Conceptual Model(Running) AccountNumber : NatBalance : MoneyLimit : MoneyHistory : List[Date,Money]CustomerName : StringBirth-Date : DateAddress : AddressIncome : Money1-20-NOwnOpen-DateBankIS-ASaving AccountNumber : NatInterest : PercentBalanceProcesses and RulesAccount USE : First open --- then deposit – then (withdraw-deposit)* - then Close-or-be-closed... Information SystemsFirst generation of CMs : “Entity first”E/R Conceptual ModelAutomaticTellerMachineATM-Reference : StringCash : HiddenBank : StringTransaction : List[Money]History :List[Card-Nb,Acnt-Nb,MoneyCustomerName : StringWithdraw1-20-NAmountDateBank-CardNumber : NatAccount-Nb: NatCode : StringProcesses and RulesATM-use : First enter-card – then enter-code – then enter-transaction—get money... Information SystemsFirst generation of CMs : “Entity first”E/R Conceptual ModelBookReference : StringName : StringAuthor : StringPublisher : StringStudentName : StringSubscription-NbSemesterBorrow0-N0-3Date-OutDate-BackProcesses and RulesFirst subscribe-- Get library-card – (Borrow – Return –or– Penality)*--(be)Unsubscribe(d)... Information SystemsFirst CM generation : Process With Petri NetsWhat is a behavioral process in IS---at the highest-abstract-level?
  • States (instances) : In terms of (un-)availability. That a state instance is regarded as a resource
  • Example : An account (instance) is a resource, a book (instance) is a resource.
  • (State-based) Actions: The allowed ordering causality between states (instances) via actions (i.e. operations, methods).
  • Example : First open-account, then deposit then looping withdraw-depsit-then close
  • ... Information SystemsFirst CM generation : Process With Petri Nets
  • Author :Carl-Adam Petri Live currently in Hamburg (honorary Professor at the Univ.)
  • History:Model introduced by C.A. Petri in 1962
  • (Physics) Ph.D. Thesis: “Communication with Automata”
  • PNs Applications:Distributed computing, manufacturing, control, information systems, communication networks, transportation…
  • Purpose: PNs specify / validate / verify explicitly and graphically:
  • sequencing/causality actions on states
  • conflict/non-deterministic choice actions
  • True concurrency actions on states
  • ... Information SystemsFirst CM generation : Process With Petri Nets(Introductory) Reference:
  • Tadao Murata. “Petri nets: Properties, Analysis and Applications.” Proc. of the IEEE, 77(4), 1989.
  • Wolfgang Reisig, “Petri Nets”, Springer, EATCS Monographs on Theoretical Computer Science, 1985 (Also in German).
  • ... Information SystemsFirst CM generation : Process With Petri NetsConceptual philosophy under Petri nets:
  • In any system, we have resources
  • Artifact-based resources : data, objects, events,
  • Real resources : printers, buffers, CPUs
  • There is generally, a number of available instances for each kind of resource in the system.
  • Actions (behavior, dynamics) in the system allows:
  • consuming (using) some resources and
  • producing new ones or updating existing ones (under some conditions).
  • ... Information SystemsFirst CM generation : Petri Nets Concepts
  • With each kind of ressource is described by:
  • a PLACEgraphically as circle is associated
  • Ressource instances are included as:
  • BLACK DOTS (called TOKENS) within the corresponding ressource kind place.
  • Actions called TRANSITIONS are:
  • graphically represented as a BOX or RECTANGLE.
  • Ressources consumption are captured by:
  • INPUT ARCS---valuted or inscribed by the numbers of required ressouces--- From the corresponding ressource place to the associated action box.
  • Ressources production or changes are captured by:
  • OUTPUT ARCS---valuted or inscribed by the numbers of produced ressouces--- From the associated action box to the corresponding target resource place
  • PETRI NETS ARE BIPARTITE GRAPHS... Information SystemsFirst CM generation : Petri Nets ConceptsP1INPUT place withfive (5) tokens as MarkingINPUT arc withtwo (2) (required tokens) as arc-inscription2T1Transition named T14OUTPUT arc withFour (4) (produced tokens) as arc-inscriptionP230OUTPUT place withthirty (30) tokens as marking... Information SystemsFirst CM generation : Petri Nets IllustrationsToOpenBankOKClosedOpenAcntAcntStateDepositOpenedDepositTransfertWithdraw... Information SystemsFirst CM generation : Petri Nets IllustrationsPenality2PayToBorrowBooks@Library30611CardReturnReturn&PenaltyBorow1ToReturnBorrowed-Books... Information SystemsFirst CM generation : Petri Nets Strenghtsand choice... Information SystemsFirst CM generation : Petri Nets Strenghts... Information SystemsFirst CM generation : Petri Nets Typical UseCommunicationProtocolsReceive msgSend msgToReceiveToSendSend AckReceive Ack... Information SystemsFirst CM generation : Petri Nets Typical UseOperating SystemsProduceBufferConsume... Information SystemsFirst CM generation : Petri Nets Typical UseEmbedded SystemsMachine-ItemsCoins3$4$2$GetWaterGetCigaretteGetCaffeCaffe25PWaterCigarette75PChange... Information SystemsFirst CM generation: Petri Nets FormalismsA Petri nets in a five tuples PN = (P, T, W, M0)
  • P = {p1,p2, ....,pn} is a finite sets of places (circles)
  • T = {t1, t2, ...,tq} is a finite set of transitions (boxes)
  • F  (P x T)  (T X P) is a finite set of arcs. An input (resp. output) ) arc joins a place to transition (resp. transition to place). NEVER PLACE TO PLACE or TRANSITION TO TRANSITION.
  • W : F  {1,2,...} is a weight function attached to the arcs. If the weight in missing it is implicitly one.
  • M0 : P  {0,1,2,....} is the intial marking. M0(p), p  P is the marking (i.e. numbers of tokens) of the place p.
  • ... Information SystemsFirst CM generation: Petri Nets FormalismsNotations :
  •  t : the set of input places of transition t. that is the set of places p such that (p,t)  F.
  • t : the set of output places of transition t. That is, p such that (t,p)  F.
  • p : the set of input transitions of place p. that is the set of transitions such that (t,p)  F.
  • p : the set of output places of transition t. That is, t such that (p,t)  F.
  • ... Information SystemsFirst CM generation: Petri Nets DyanmismsDynamics of Petri nets :
  • A transtion t is said to be enabled if, whatever p  t , p contains a number of tokens greater of equal than W(p,t) (i.e. M(p)  W(p,t))
  • Firing an enabled transition t, consists in :
  • Removing W(p,t) tokens from each p  t
  • Adding W(t, p) tokens from each p t
  • That is, M‘(p) = M(p) – W(p,t) + W(t,p)
  • A sequence of transitions firing is generally represented by = <ti1, ti2 , ....., tik>, and
  • We say that the corresponding resulting marking is: M0 -- --Mk
  • ... Information SystemsFirst CM generation : Petri Nets DynamismsOperating Systems AnimatedProduceBufferConsume... Information SystemsFirst CM generation : Petri Nets DynamismsEmbedded Systems AnimatedMachine-ItemsCoins10726183$4$5$GetWaterGetCigaretteGetCaffeCigaretteCaffe25PWater211175PChange175100... Information SystemsFirst CM generation : Petri Nets DynamismsChimical Reactions : 2H2 + O2  2H2O2tH22H2OO2... Information SystemsFirst CM generation : Petri Nets InternalsIncidence matrix : A = [aij]
  • is an n  m matrix of integers
  • its typical entry is given by
  • aij = aij+ - aij-
  • Where aij+ = w(T,P) is the weight of the arc from transition T to its output place P
  • and aij- =w(P.T) is the weight of the arc from the input place P to the transition T.
  • ... Information SystemsFirst CM generation : Petri Nets Internals
  • Given an initial marking M0, let  be a firiable sequence of transitions which applies to M0.
  • The counting vector V of is the vector V = [v1,v2,..,vj,...vq] is the numbers of times tj is included in .
  • If M is the marking obtained by firing , then:
  • Mt = M0t + AVt.
  • With t denotes the transpose.... Information SystemsFirst CM generation : Petri Nets InternalsIllustration:t4t1t2p2p142t3p322p4... Information SystemsFirst CM generation : Petri Nets Internalst1 t2 t3 t4p1 1 -2 -1 0
  • A = p20 4 0 -1
  • p30 0 1 -1p40 0 -2 2Let M0 = [3,0,0,2] and  = <t2,t3,t4>,that is V= [0,1,1,1] . Then M = [0, 3, 0, 2] using the formulas.... Information Systems
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